Wondered if anyone could point me in the right direction for resolving and error I am getting in workflow.  I have had it in both my production server and my development server.

It seems to be an interval of "works for 4-5 emails" then throws an error and terminates workflows for 30 minutes.  Then without changing anything, will randomly work again.

I have spoken with my system admin, server admin, and email admin.  Email admin says nothing has changed on the email server.

In my dev environment, all the emails are going to the same person (me) since I am testing processes.  It is terminating and given this error on multiple workflows in different processes.  I can go into workflow admin console and send a test email.  Sometimes it works sometimes I get the error.  I have tried restarting the workflow service and subscriber numerous times.  I have even restarted the server itself.

Is there something else I should be checking.

Any help is appreciated.  Thanks.