Clearing Log Shipping config Secondary server inaccessible
I had similar error few months ago and solved by this. 

USE master;
GO

EXEC master.dbo.sp_delete_log_shipping_primary_secondary
    @primary_database = N'&lt;PrimaryDatabase&gt;'
   ,@secondary_server = N'&lt;SecondaryServer&gt;'
   ,@secondary_database = N'&lt;SecondaryDatabase&gt;'

GO