EC200U-CN A17M08 – AWS IoT TLS Handshake Failed Error 579 / QSSLOPEN – Urgent Technical Support Required

Diac1 · August 17, 2026, 6:35am

Hello Quectel Support Team,

We are currently integrating an EC200U-CN modem with AWS IoT Core using MQTT over TLS 1.2 with mutual TLS authentication.

We are blocked by a persistent TLS handshake failure and need urgent technical assistance.

We previously raised a related issue here:

Previous Quectel thread – EC200U-CN AWS IoT TLS handshake failed

Unfortunately, we have not received a response from the Quectel team even after updating the thread.

Module Information

Module: EC200U-CN
Firmware: EC200UCNAAR03A17M08
Application: AWS IoT Core
Protocol: MQTT
MQTT Port: 8883
TLS: TLS 1.2
Authentication: AWS IoT X.509 mutual TLS

EC200U-CN AWS IoT TLS Handshake Failed - Error 579 / QMTOPEN 0,5 - A13M08

Network connectivity is working

The modem successfully:

Registers on LTE network
Activates PDP context
Obtains an IP address
Resolves the AWS IoT endpoint
Successfully reaches the AWS endpoint using AT+QPING

Example:

AT+QIACT?+QIACT: 1,1,1,"10.112.213.56"OK

AWS endpoint:

a7t6qe56nuogw-ats.iot.ap-south-1.amazonaws.com

Therefore, this does not appear to be an APN, PDP, DNS, or basic network connectivity problem.

TLS Configuration
We uploaded the following certificates successfully to UFS:

AmazonRootCA1.pemdeviceCert.pemprivateKey.pem

The modem reports the expected file sizes:

AmazonRootCA1.pem  = 1188 bytesdeviceCert.pem     = 1220 bytesprivateKey.pem     = 1679 bytes

TLS configuration:

AT+QSSLCFG="cacert",2,"UFS:AmazonRootCA1.pem"OK
AT+QSSLCFG="clientcert",2,"UFS:deviceCert.pem"OK
AT+QSSLCFG="clientkey",2,"UFS:privateKey.pem"OK
AT+QSSLCFG="seclevel",2,2OK
AT+QSSLCFG="sslversion",2,3OK
AT+QSSLCFG="ciphersuite",2,0xFFFFOK
AT+QSSLCFG="sni",2,1OK
AT+QSSLCFG="ignorelocaltime",2,1OK

All configuration commands return OK.

Actual TLS Failure

The important point is that we tested TLS directly using QSSLOPEN, without MQTT.

Command:

AT+QSSLOPEN=1,2,0,"a7t6qe56nuogw-ats.iot.ap-south-1.amazonaws.com",8883,0

Result:

+QSSLOPEN: 0,579

Then:

AT+QIGETERROR

returns:

+QIGETERROR: 579,ssl handshake failed

Therefore, the failure occurs during the TLS handshake itself, before MQTT connection establishment.

When using MQTT, we consequently receive:

+QMTOPEN: 0,5

Manual AT Command Testing Also Failed

We also performed the connection manually using AT commands rather than our application firmware.

The same TLS handshake failure occurs.

Therefore, this does not appear to be caused by our application MQTT implementation.

We have also tried:

TLS 1.2
SNI enabled
seclevel=2
ciphersuite=0xFFFF
Correct CA certificate
Correct client certificate
Correct private key
Manual QSSLOPEN
MQTT QMTOPEN

But the TLS handshake still fails with:

579 - ssl handshake failed

Could the Quectel technical team please investigate the following urgently?

1. Is error 579 a known TLS/firmware issue on:

EC200UCNAAR03A17M08

2. Is there a known firmware bug/interoperability issue with AWS IoT Core?

3. Is `A17M08` the recommended/latest firmware for AWS IoT TLS connections?

4. Is there a newer firmware version that fixes TLS handshake error 579?

If yes, please provide the exact firmware version/download package recommended for EC200U-CN.

5. Please confirm the correct `QSSLCFG` configuration for AWS IoT Core.

In particular:

seclevelsslversionciphersuitesniignorelocaltime

6. Please explain what specifically causes:

+QSSLOPEN: 0,579+QIGETERROR: 579,ssl handshake failed

on EC200U-CN.

This Is Blocking Our Product Development

We have already spent significant time validating the network connection, certificates, MQTT configuration, and manual AT-command sequence.

The modem can establish cellular connectivity and reach the AWS endpoint, but the TLS handshake consistently fails.

We therefore need Quectel engineering support rather than further generic MQTT troubleshooting.

Please escalate this case to the EC200U-CN firmware/TLS engineering team and provide a concrete resolution or recommended firmware as soon as possible.

This issue is currently blocking our AWS IoT integration and product development.

Attached Full AT command logs for your reference need immediate response from support team

Thank you.

EC200U_A17M08_AWS_IoT_TLS_Handshake_Failure_Manual_AT_Logs.zip (1.1 KB)

fazrulredzuan · August 20, 2026, 4:37pm

Dear Customer,

Thanks for the detailed report and the AT log, that’s exactly what we needed. I’ve reviewed the attached EC200U_A17M08_AWS_IoT_TLS_Handshake_Failure_Manual_AT_Logs.txt and I can see the root cause.

Root cause: In the attached session the module was freshly powered on (POWERON_RESET), and before QSSLOPEN only the CA certificate was applied to SSL context 2:

AT+QSSLCFG="cacert",2,"UFS:AmazonRootCA1.pem"   → OK
AT+QSSLOPEN=1,2,0,"...",8883,0                  → +QSSLOPEN: 0,579

The clientcert, clientkey, and seclevel commands from your description were not present in this session. AWS IoT Core requires mutual TLS, so the device must present its own certificate and key, and seclevel must be 2 (server + client authentication). Without those, AWS terminates the handshake, which surfaces on the module as error 579 ssl handshake failed. QSSLCFG settings are per-session and are cleared on reboot, so the full set must be re-applied after each power-on, before QSSLOPEN.

Please apply the complete configuration in this order and retry:

AT+QSSLCFG="sslversion",2,4
AT+QSSLCFG="seclevel",2,2
AT+QSSLCFG="cacert",2,"UFS:AmazonRootCA1.pem"
AT+QSSLCFG="clientcert",2,"UFS:deviceCert.pem"
AT+QSSLCFG="clientkey",2,"UFS:privateKey.pem"
AT+QSSLCFG="ciphersuite",2,0xFFFF
AT+QSSLCFG="sni",2,1
AT+QSSLCFG="ignorelocaltime",2,1
AT+QSSLOPEN=1,2,0,"a7t6qe56nuogw-ats.iot.ap-south-1.amazonaws.com",8883,0

Expected result: +QSSLOPEN: 0,0.

Answers to your specific questions:

Is 579 a known firmware issue on A17M08? No. 579 is a generic “TLS handshake failed” result, not a firmware defect. It reflects the handshake being rejected by the peer — here, because no client certificate was presented.
Known AWS IoT interoperability bug? No known interoperability issue between A17M08 and AWS IoT Core. We have working AWS IoT mTLS references on this firmware.
Is A17M08 recommended/latest for AWS IoT TLS? A17M08 fully supports AWS IoT mutual-TLS. No firmware change is required to resolve this case.
Newer firmware that fixes 579? Since this is configuration-related, a firmware upgrade will not change the behavior. Applying the full mTLS config above resolves it. If you’d still like the latest release for other reasons, let me know your region/carrier and I’ll check availability.
Correct QSSLCFG for AWS IoT Core: as listed above — seclevel=2, sslversion=4 (or 3 for TLS 1.2 only), all three cert/key items bound, sni=1, ciphersuite=0xFFFF, ignorelocaltime=1.
What causes 579 / “ssl handshake failed”: the handshake is aborted by the server or fails local validation. The most common causes on EC200U are (a) seclevel not set to 2 with AWS mutual TLS, (b) client certificate/key not bound to the SSL context, (c) SNI disabled, or (d) module clock wrong with time-check enabled. In your log, (a) and (b) apply — client cert, client key, and seclevel=2 were not set in the session before QSSLOPEN.

If the handshake still fails after applying the full sequence above, please send:

The output of AT+QSSLCFG="clientcert",2 , ...="clientkey",2 , ...="cacert",2 and AT+QSSLCFG="seclevel",2 (to confirm binding),
Confirmation that deviceCert.pem is the AWS-issued device certificate and is Active with an attached IoT policy allowing iot:Connect,
AT+CCLK? output (to rule out a clock/validity issue).

Best regards,
Fazrul Redzuan

Diac1 · August 21, 2026, 10:24am

EC200U_A17M08_Full_mTLS_Sequence_579_Log2_PostReset (1).txt (2.3 KB)

Thank you for the detailed troubleshooting sequence. We applied your exact recommended AT command sequence, in the exact order specified, on a freshly powered-on module — including the certificate binding confirmation and clock check you requested.

Module firmware confirmed via ATI : EC200UCNAAR03A17M08

The result is unchanged: +QSSLOPEN: 0,579.

The attached log includes:

Full network registration status (AT+CEREG?, signal quality, operator/band info)
Certificate/key binding confirmation, queried immediately before the handshake attempt (cacert, clientcert, clientkey, seclevel — all confirmed correctly bound)
Module clock verification (AT+CCLK?)
The handshake attempt and resulting error (AT+QSSLOPEN, AT+QIGETERROR)

Please let us know how you’d like to proceed from here.

Diac1 · August 21, 2026, 11:15am

We followed and tested our EC200U module with a public free server (test.mosquitto.org, port 8884) to rule out AWS-specific issues.

Result: TLS handshake still fails with error 579.

Log attached shows:

Network OK
PDP context active (IP: 10.219.144.36)
All SSL settings configured and confirmed
AT+CCLK? correct
AT+QSSLOPEN → +QSSLOPEN: 0,579
AT+QIGETERROR → ssl handshake failed

Since the same error occurs with a free public server, this confirms the issue is not configuration-related but likely a firmware bug in version EC200UCNAAR03A17M08.

Request: Please provide the latest firmware that fixes TLS handshake issues on EC200U-CN.

PFA of logs for you referenceLet us know if you need any additional logs or tests.

AT_CMD_mosqitto_free_server_certi_test_tls - Copy.txt (5.8 KB)

fazrulredzuan · August 22, 2026, 4:23am

Dear Customer,

The firmware that you are currently using is the latest firmware we have on our shelf. Thanks for the follow-up logs and for confirming the certificate binding the QSSLCFG side now looks correct. Before we look at firmware, I checked the network layer in both sessions, and that’s where the problem is:

Log 2 (AWS): the PDP context was not active at handshake time:

AT+QIACT?
OK                          ← no context listed
AT+CGPADDR
+CGPADDR: 1,"0.0.0.0"       ← no IP assigned

You issued AT+CFUN=1,1 at the start, which deactivates the context, but AT+QIACT=1 was never re-run afterward, so the module had no IP when QSSLOPEN was called.

Log 3 (mosquitto): the session contains no network commands at all (no CEREG / QIACT / CGPADDR). The IP 10.219.144.36 mentioned in your message does not appear in the attached log, so we can’t confirm an active bearer there either.

A 579 ssl handshake failed returned without a confirmed IP + reachability in the same session is inconclusive the same symptom appears whenever the data context isn’t up. That common factor is present in both failing logs, which is a much more likely explanation than an identical firmware fault against two unrelated servers. A17M08 is a current, supported build and completes AWS IoT mutual-TLS in the field, so I’d like to rule out the network layer with a clean, single-session capture before any firmware discussion.

Please run this exact sequence in one session, after a fresh boot, and send the full log:

AT+CFUN=1
AT+CPIN?
AT+CEREG?                 // wait for 0,1 or 0,5
AT+CSQ
AT+QIACT=1
AT+QIACT?                 // MUST show a real IP, e.g. +QIACT: 1,1,1,"x.x.x.x"
AT+CGPADDR                // MUST NOT be 0.0.0.0
AT+QPING=1,"a7t6qe56nuogw-ats.iot.ap-south-1.amazonaws.com"   // confirm reachability now
AT+QSSLCFG="sslversion",2,4
AT+QSSLCFG="seclevel",2,2
AT+QSSLCFG="cacert",2,"UFS:AmazonRootCA1.pem"
AT+QSSLCFG="clientcert",2,"UFS:deviceCert.pem"
AT+QSSLCFG="clientkey",2,"UFS:privateKey.pem"
AT+QSSLCFG="sni",2,1
AT+QSSLCFG="ignorelocaltime",2,1
AT+QSSLOPEN=1,2,0,"a7t6qe56nuogw-ats.iot.ap-south-1.amazonaws.com",8883,0

Expected: +QSSLOPEN: 0,0.

If it still fails after QIACT? shows a valid IP, please also run this two-step isolation test against the Mosquitto server you already have set up. It separates the TLS stack from the mutual-auth path:

Server-auth only (no client cert):

AT+QSSLCFG="seclevel",2,1
AT+QSSLCFG="cacert",2,"UFS:mosquitto_ca.pem"
AT+QSSLOPEN=1,2,0,"test.mosquitto.org",8883,0

Mutual auth:

AT+QSSLCFG="seclevel",2,2
AT+QSSLCFG="clientcert",2,"UFS:client_cert.pem"
AT+QSSLCFG="clientkey",2,"UFS:client_key.pem"
AT+QSSLOPEN=1,2,0,"test.mosquitto.org",8884,0

If step 1 fails → the issue is network / CA / TLS reachability, not mutual TLS.
If step 1 passes but step 2 fails → the issue is the client certificate/key path (key–cert mismatch or format), not the firmware.

Please send the complete single-session log including the QIACT?, CGPADDR, and QPING lines. Once we have a capture with a confirmed active context, I can escalate to R&D with a complete picture if the handshake still fails but the current logs don’t yet show TLS being attempted over a live connection.