27/07/2023 12:20:00 PM (GMT)
NHSmail Reference : INC37267524
Microsoft Reference : TM661556
Issue Status : RESOLVED
Issue Description : Users may be unable to access the Microsoft Teams Session Initiation Protocol (SIP) gateway.
Final Update : 27/07/2023 14:29:00 PM – To mitigate the database errors, Microsoft have optimized and redirected traffic to an alternate section of SBC infrastructure. They have further confirmed impact has been remediated after a period of extended monitoring.
Scope of impact : Impact is specific to some users hosted through the affected infrastructure in Europe, Middle East, Africa and North America.
Root cause : A recent standard service update inadvertently resulted in Session Border Controllers (SBCs) to become unresponsive, resulting in user devices being unable to access the SIP gateway.
Next steps : Microsoft are reviewing their recent standard service update procedures to understand why this resulted in SBCs becoming unresponsive, in order to help prevent similar impact from happening again.
They are continuing to further analyze database and SBC logs to identify the source of the 403 database errors.