Few weeks ago, during a audit, I have a lot of error 777970008 in the errorlog file from the SCOM instance.
All 5 minutes, we had 4 lines more in the ErrorLog and the file growth a lot.

After using google to find a cause of this message and resolve it, I finally find a good blog from Kevin Holman.
I downloaded the script here and executed the part for the error 777970008 only:

DECLARE @localized_string_msgnum_777970008 nvarchar(255)

set @localized_string_msgnum_777970008 = N'Management Group with id ''''%s'''' is not allowed to access Data Warehouse under login ''''%s'''''

EXECUTE sp_addmessage @msgnum = 777970008, @msgtext = @localized_string_msgnum_777970008, @severity = 16, @lang = 'us_english', @with_log = false, @replace = 'REPLACE'

After that, the error was no more in the errorlog file.
Thank you, Kevin, for your helpful blogs.

I hope this blog can help to resolve also this issue. 😎