[Poiseuille]

Just spent 25mims composing a PM to a member who had asked me a question, pressed send and got the message "did not send, your are not logged on" when of course I am logged on, that's how I got on my profile and read the question. No drafts are shown in my list. This is I think the fourth time this has happened, doesn't seem to be related to message length. Pretty damn irritating I have to report.
Mods able to shed any light on this?

Edit: iOS btw