Replication Error: ‘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.’

This error is caused Intermittently by the Log reader agent in the transnational replication. When you observe the error, the database principal ‘dbo’ associated to the login mapped to the ‘dbo’ user cannot be impersonated. The database owner or login associated to ‘dbo’ user are not ‘sa’ but other windows authentication/SQL authentication login.

Solution:

1. Stop the Log reader agent
2. Change the ownership of the database using the below query:

ALTER AUTHORIZATION ON DATABASE::Databasename TO sa;
GO

3. Restart the Log Reader Agent.

Conclusion:

It is always advisable to map the ‘dbo’ user of the login to ‘sa’ to avoid the intermittent issues with Log reader agent in Transnational Replication.