When I registered, the email address I wanted to use was rejected as illegal. The address I wanted to use contains a plus sign (+) to the left of the @, and is not illegal. (RFC 822 page 45 has list of not-valid chars in email addresses, and + is not one of them.)

I don't understand why you are rejecting email addresses (a) because you wrote software that apparently doesn't know what the rules are; (b) while failing to consider that a non-functional address will keep me from registering (as I won't get the email to complete registration). You don't prevent me from trying to register as president@whitehouse.gov or billg@microsoft.com. Why try to prevent me from using any address at which I can receive email? (Particularly when it's a _valid_ address and your code simply blocks it because it's buggy!)

Hopefully you will let me know that this is fixed and I can change my email address to what I want to use.

Welcome.

The filter when I put it in place was a long time ago and I've received no feedback on it -- at least not that I recall.

I'll go and revisit it.

Thanks