Does it happens ALWAYS and the login doesn't work?
Change the password to comply with BnS's rules (they don't enforce them on registrering).
Does it happens sometimes?
Ignore it and try again.
I was reading the source code.
The error occurrs after a failed attempt to verify the email against a regular expression.
Please, confirm if your email matches it on: https://regex101.com/r/Uql7N9/1
(To make it easier to test, you can test up to the @ and after the @, to make sure both parts are matching)
.infofails to match the regular expression, which expects 2-3 letters at the end.