Error 14421 log shipping

Hi all,
I'm getting the following error below from my secondary server and the only process that fails intermitently so far is the copy process on the secondary. I need help please

Executed as user: Domain\SQL Service Acct. The log shipping destination SERVERNAME.DATABASENAME is out of sync by 990 minutes. [SQLSTATE 42000] (Error 14421) Associated statement is not prepared [SQLSTATE HY007] (Error 0). The step failed.

Any help much appreciated

Matey