Hi,
This error is not related to RunMyProcess but caused due to unavailabity of GMail smtp provider at that time. I guess in the manual task, you are notifying the assignee by email that uses Gmail provider.
It is caused sometimes due to some unknown reasons (at Google) when you send email through gmail smtp and it is a temporary system problem. It has been running well now. Do you still get this error ?
Here are some links to such posts on Google Product Forum from others:
Regards,
Pray Desai,
Fujitsu RunMyProcess.