--https://support.microsoft.com/de-de/help/2000274/how-to-fix-permission-issues-when-moving-msdb-database-between-different-instances
--
use msdb
go
-- Backup the Agent certificate from the remote server to a file
BACKUP CERTIFICATE [##MS_AgentSigningCertificate##] TO FILE = 'd:\ServerInstall\MS_AgentSigningCertificate.remote_server.cer'
go
use master
go
-- re-create...