Signup form fails to verify valid email address

[henk84]

Hi

Trying to signup on https://pim.etesync.com/signup gives me an error:

Mail server not found for this email address. Please verify your email address and try again.

This is very likely due to some (javascript) code doing insufficient validation of the domain: the domain I use does not have an MX record, for several reasons that are mostly irrelevant.
Domains do not need an MX record to work for email, as the RFC requires senders to use the A record instead when no MX record is found. Sending an email to the email address given would probably work just fine.

Please go over the validation code and consider using a (good) library for validating email addresses. This everything but trivial, see e.g. https://e-mail.wtf/

Thanks!