I tried sending an email to a user and was unable to do so after close to 20 attempts. For the first 10 or so attempts I got the following message:

"We're sorry, but your request is missing some critical information.
Please click the back button and try again."

For the second 10 I got:

"An error occurred while trying to send your email to XXXXXXX
The recipient's mailbox was unavailable at the time of sending.
Please try again later."

I've have on occasion sent emails before and I usually have gotten two or three of the first message before the email did go through.

I'm wondering if this could be due to the recent forum changes.