You may encounter an issue that emails that you are forwarding from your Microsoft Teams are rejected by Kayako with the following message:
Mail can't be processed through due to: INVALID_FROM_ADDRESS
This issue most probably happens due to an invalid 'From' address, as the service is using the caller's number in the 'From' field instead of a valid email address.
You need to work with your IT department to change the 'From' address and resolve the issue. The best way to retrieve the header information is to use API. Once you have the header information, you can work with your IT department to change the 'From' address and resolve the issue.