Email address is not passing registration

I've installed miniBB in one of my sites, and everything is going well except... that one of the users has an email looking like firstname-.name@provider.com. And miniBB considers that "-." is a mistake (OK, it's an uncommon email, but it's like this, and this user is very important for that forum).
Thank you

The file you need to edit is bb_func_checkusr.php

Find expression:

"^[0-9a-z]+([._-][0-9a-z_]+)*_?@[0-9a-z]+([._-][0-9a-z]+)*[.][0-9a-z]{ 2}[0-9A-Z]?[0-9A-Z]?$"

Try to set it like:

"^[0-9a-z.-]+@[0-9a-z]+([._-][0-9a-z]+)*[.][0-9a-z]{2}[0-9A-Z]?[0-9A-Z ]?$"

It works. Thank you very much.