Exchange 2019. MSExchange Common Error 4999?

Question

Microsoft Exchange

MS Windows 2019/MS Exchange 2019 - all updates for February 17, 2021 February
16, afternoon, installed CU7 (KB4602269), .NET (KB4601887), stack update (KB4601393)
February 17, night, scheduled restart.
After that, a cyclic restart of the MSExchangeMailboxAssistants service began.

Watson report about to be sent for process id: 26956, with parameters: E12IIS, c-RTL-AMD64, 15.02.0721.008 .
ErrorReportingEnabled: False

The first page of google seems to have been read))

Answer 1

Everything was decided by installing CU8

Answer 2

Try to see if all the necessary services have started.
Next set-mailboxserver -OABGeneratorWorkCycleCheckpoint 49.0:00:00 -identity Here
is an article for 2013, but I saw exactly the same problem in 2016 and most likely it will also work for 2019.