SQL SERVER - FIX - REPLICATION ERROR: Cannot execute as the database principal because the principal "dbo" does not exist

I was dealing with a replication issue, the Log Reader Agent was failing with the following messages:

Error messages:

The process could not execute 'sp_replcmds' on 'ServerName'. (Source: MSSQL_REPL, Error number: MSSQL_REPL20011)

Get help: http://help/MSSQL_REPL20011

Cannot execute as the database principal because the principal "dbo" does not exist, this type of principal cannot be impersonated, or you do not have permission. (Source: MSSQLServer, Error number: 15517)

Get help: http://help/15517

The process could not execute 'sp_replcmds' on 'ServerName'. (Source: MSSQL_REPL, Error number: MSSQL_REPL22037)

Get help: http://help/MSSQL_REPL22037

In several forums you will see a discussions about it, but most of them didn't provide a final solution for it.

The solution for it is really simple:

ALTER AUTHORIZATION ON DATABASE::[DatabaseName] TO sa 

The reason is, the DB was restored from another environment or was restored from an old SQL Version.