Invalid Request when sending message

[chauvetp]

Hello all,

Has anyone seen the following? I had a user try to send an e-mail (client Firefox 3.0.10 - Windows XP) to me and got the error message in the screenshot below (An invalid request was made + details):




(image edited to remove the user's e-mail address and last name only).

We haven't seen this error before here but we just updated to 5.0.16 from 5.0.13 last Friday (May 15th).