I am noticing that private messages I am sending are getting stuck in the "Outbox." Can you please look into this? Thanks!

Have the message recipients responded to them? PMs stay in your outbox until they are read by the recipient, when they are then moved to the Sent folder. The Sent folder doesn't clear, either, but the oldest message gets "bumped" by the new one once the folder fills.

Thanks for the clarification. It works a little different than regular email.