Unable to logon to SBS 2008 as domain admin

Hi guys,

I am facing strange issue with my SBS 2008 DC server.

After restart I am unable to log on with domain admin user as well as with other 2 accounts with the same admin rights. There is written that Username or password is incorrect, but under the safe mode it works.

I am able to login under the safe mode only. There was no change on the server, it is running 3 years without any issue.

I was working on connection of NAS Synology RS812 to network, there was no other work on nework.

Can anybody help me please?

Thanks,

Jan

Šerý