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Exchange Server error in '/owa' application
ASSERT: HMACProvider.GetCertificates:protectionCertificates.Length<1 Description: An unhandled exception occurred during the execution of the current web request. Please review the stack tr...
- Ok i found solution. Use this to create new certificate https://docs.microsoft.com/en-us/exchange/troubleshoot/administration/cannot-access-owa-or-ecp-if-oauth-expired
And after creating the certificate you must wait like a hour or more for changes work. Restart dont change the wait time 🙂
My certificate was valid till 2027 but my Windows 2019 Core server did updates (2 Feb 2022) and rebooted and after the reboot ecp and owa was broken. In the event log, i could see constant info messages to say that all the exchange items were either missing or corrupt. To fix this, i ran the commands to create a new OAuth certificate, removed the old one and then rebooted. I then re-ran the CU11 security update from January 2022 and rebooted again. It took a while but Exchange 2019 was happy again and both ecp and owa working fine. (Edward van Biljon - Office Apps & Services MVP)