As a workaround, a rule can be added to the Exchange Admin Center in Office 365 to allow voicemail messages from Microsoft. To create this rule:
1. Navigate to Exchange Admin Center > Mail Flow > Rules
2. Click on "Create a new rule"
3. Create a new rule that:
Name: Teams Bypass
Apply this rule if: "The message type is"> include the message type > "Voice Mail"
and
Sender's IP address is in the range "13.107.64.0/18, 52.112.0.0/14, 52.120.0.0/14, 52.238.119.141/32, 52.244.160.207/32, 2603:1027::/48, 2603:1037::/48, 2603:1047::/48, 2603:1057::/48, 2620:1ec:6::/48, 2620:1ec:40::/42"
[please check Microsofts documentation for their latest Teams IP addresses - see https://docs.microsoft.com/en-us/office365/enterprise/urls-and-ip-address-ranges]
Do the following...
"Require TLS Encryption"
Chose a mode for this rule: Enforce
Check "Stop processing more rule"
4. Click Save
5. Ensure the completed rule is placed above the Proofpoint block rule
The completed rule will look like:
