Micollab audio issues with IVR

[SebJenkins]

Hi there,

We have recently switched from an on-prem Mivoice phone system with physical MITEL handsets to a MiVoice Business cloud solution and MiCollab softphones

Our contact centre have reported a strange issue where they call a destination and almost always always the call is answered by an IVR. The initial greeting is fine in terms of audio quality, however once they press an option from the menu, ie. 1,2 etc then they get the next message but it's at this point that the audio becomes crackly/robotic/distorted.
Didn't have a clue what this means or what to do about it until one of the users discovered that if they place the call on hold as soon as they hear the distorted audio then immediately take it off hold, the audio quality is perfect.
This method has been tried and tested each and everytime the users run into audio issues when navigating through customer IVRs.
Anyone know what this means ? Is it something to do with SIP invite/reinvite or is that completely irrelevant ?

Thanks in advance! :-)

[Dutch]

couple of stuff to setup:

1. COS IVR / Trunk > Make sure you set the following options
Music on hold on transfer = YES
Use local music on hold = YES

2. SIP Peer
w/e the provider sheet mentions and people say just ignore them when you use an MICC with IVR and set the following option (MICC IVR is never part of Interop testing or only briefly as far as I know)
Suppress Use of SDP Inactive Media Streams = YES (force sendrcv in SDP whenever possible)

3. IN the IVR in the WORFLOW as always use subroutines to efficiently handle memory usage and every item that starts a message try out the following:
Use a 2 second delay before the message starts.
(we have encountered situations where SDP and RE-Invites if SIP) where we need to give insert a delay to SDP negotiation to be effective before the message starts. We have encountered a per provider situation where messages would even result in NO Audio.

Whenever there is an IVR in combination with a MiVB with a SIP Peer you always need to make sure everything from the baseline works together. simple 1-on-1 calls is fine but when an IVR plays a message or transfers and you have audio issues the above probably will resolve. You mention hold and retrieve. The fact that makes a difference just triggered me to reply with the above.

Also if all else fails something you could test with is disabling PRACK. Not all calls/providers are efficient in using 180 or 183 and disabling PRACK in our country situations help .... SOMETIMES (only).

Just my 2 cents and I hope this helps, but anything can be situational. Worst case give me a pm if you need further assistance.

Dutch