When I try to open Trace in Architect, I got error saying
User <LocalUser> doesn't have access into system.
I granted permissions to my windows user account in MSSQL under related databases but without any success.
Does it say LocalUser? This message normally indicates that there is no record in the BusinessPartner table with a field UserName being equal to your Windows user name (e.g. COMPUTER\username)
Yes, it was this case. Adding such BusinessPartner solved the problem.