When trying to send another user a message, I get an empty page, message not sent
After composing the message (click on button in the user's profile), I get an empty page. I couldn't find any new errors in the cog log. The message does not seem to be sent - at least I didn't get anything by email (sent it to my own test account). The message (or some part of its info) seems to be saved, but I cannot access it in the admin interface, I get a timeout error.