EC21-E command AT+QDAI= ERROR

Hi All!
I have an issue here with a Quectel EC21-E behaviour and i need some help.

After reading the AT-Command sheets carefully our driver-software is not able to set the „Digital Audio Interface Configuration“ (AT+QDAI=) at all times.
We have other devices of the same kind with the identical modem and identical driver-software, where the command works.
The question is what are the preconditions for the command „AT+QDAI=“ to not ERROR? Are there any restrictions or must-do-procedures before „AT+QDAI=“ ?

A short insight in the issue:

14:53:52.800: AT+QDAI?
14:53:52.820: +QDAI: 3,0,0,4,0,0OK
14:53:52.820: AT+QDAI=1,0,0,4,0
14:53:52.860: ERROR

I tried to do the AT+QDAI commands at several different times (e.g. before and after network registration) and also at different Modes (CFUN=0, CFUN=1, CFUN=4).

I am thankful for every information regarding this Command.

Further Information:
Modem-Revision: EC21EFAR02A09M4GOK

Thanks Everyone,

Hi noah,
AT+QDAI this command is used to configure the digital audio interface, customers can define the
PCM formats by themselves. In the following conditions, the module can be used directly with default
settings (master mode, short-synchronization, 2048K clock frequency, 16-bit liner data format, 8K
sampling rate).