While you can (obviously) create an account using a plus sign in the email address; your password reset process is replacing the plus sign with whitespace; causing the password reset lookup to fail.

Hello Stephen,
Thank you for your question about using the plus (+) notation in your email. We just released a hotfix to remedy this issue you reported, but can't test it right away because our email vendor won't let us create aliases with a plus sign.
Would you mind trying again, and letting us know if the issue is resolved?
We regret any inconvenience this may have caused.

I will test again shortly. You can create test email account w/ a plain gmail address for your testing purposes; but I will look into as I have time this afternoon. ([edited]) is a valid accouunt that would deliver email to [edited] ...

still fails - same symptoms; "email not found"

Please advise -- I have missed a few bids due to not being able to get my logon information...

Here is a temporary passwd for you: BidToWin
Would you mind replying and providing the email our site sent to you? The one that leads to the password-reset page?
(We can't reproduce on this end since our email vendor won't let us create an email address with a (+) in it.)
Thanks!