Encountered this issue earlier today. I've got several Powershell scripts that I run daily/weekly and I have the script to sent the finished report to my email address. After doing a bit of research I the found link below. I would post a doc. with the actual screenshots but it's pretty straight forward as to what needs to be done. One note of caution, have a little patience. It took about 10min before it worked successfully.
Some DC's were upgraded at my DayGig over the weekend and as a result to my surprise I could not logs into some of my mail servers. This worked as a remedy (basically a permission inheritance issue).
