Block Email address on Registration
Ultimate Member allows blocking email addresses on registration, which is one of the ways to keep your site safe from malicious users.
To block an email address, go to WP Admin > Ultimate Member > Settings > Access > Other > see “Blocked Email Addresses”
You must separate each email address by a new line or enter one email per lineto block multiple addresses. See the sample below:
When a user tries to register with a blocked email address, a message will appear that the email address has been blocked.
Block entire domain
The setting also allows blocking all emails with the specific email provider e.g.
The example image above shows that email addresses with the domain "@goldinbox.net" are blocked, so when a user registers with that domain, the user will not be able to register on your site. A message will appear that your site does not accept registrations from that domain.
When a user registers an email with letters in mixed cases, the user will still not be able to register with the email used. A message will appear the email address is blocked.
You can also use the code below to make any upper case characters in the registration email address into lower case. So it can be compared to your "Blocked Email Addresses" in lower case characters.