Bast way to block hotmail/outlook/live email addresses from registration

We have SO MANY problems with users that have hotmail.com or outlook.com or other Microsoft email addresses. They often do not receive our emails, or our emails are always sent to spam. We have put so many notices throughout the website, including on the registration page telling users with those email accounts to be sure to check the spam folder and to add us to the "Safe Senders and Domains" list, but we still continue to have problems. To investigate this further, I created a Hotmail account and tried registering. And yes, our first registration email (initial registration message which includes the email confirmation link) ended up in junk mail. But even more hopeless is that Hotmail inserts all kinds of strange symbols randomly into the email (mostly = signs). This includes inserting them into the confirm_code, which results in an error page when the user clicks the link (which of course is not correct because of the inserted symbols).

SO, we want to forbid the use of email addresses from such accounts. My question is: is it possible to generate an error message and not allow registration to proceed if an email address is input that includes @hotmail or @outlook or @live. ? If so, where would we do that? Is that something that we would apply within the email field under Community Builder Field Management? For example, can we simply add @hotmail to the Registration Forbidden Words list under Parameters/Validations? Or would it be an auto action?

We welcome any and all advice!

Are you using the default pending registration message or have you supplied your own? If you have not supplied your own yet you should do so. Using the generic message could mean your email is matching every CB install that didn't change it as well. They may see that as a metric for determining spam. If you have supplied your own it sounds like it's not formatted properly.

What are the "strange codes" displaying as (e.g. weird squares)? Can you provide a screenshot and copy of the email body of a test account with the broken email?

I highly recommend you do not block one of the major email providers. Yes, you can use forbidden words to do this, but again I highly recommend you do not.

We are using a custom email message, and our system is multilingual, so it is based on a language override.

This is what part of the message looks like in English when received by Hotmail. I have highlighted weird symbol insertions in red:



And this is what the Japanese version looks like:



We have set it so that we, as admins, receive the exact same email as is sent to the user and our emails do NOT contain these weird inserted symbols. It is ONLY the hotmail (or outlook) emails that have them. So we are confident that our email is formatted properly. Also, we have hundreds of new users every month and only those with Microsoft based emails are having this trouble, so we are confident that our email is formatted properly.

You should probably also check your e-mail server settings, as well as its utf-8 settings.

Try sending through your registration process (i.e. register a temporary test user with the temporary test-mail address) a registration mail to a mail-checking service, such as www.mail-tester.com/ - Outlook and Hotmail are very sensitive to misconfigured mail-servers.

Also avoid many red-colored letters in your emails. That is typically triggering spaminess

Since our server sends out hundreds of emails every day and only those with Microsoft email accounts have troubles, we are confident that our server settings are correct. But just in case I did a test with mail-tester.com and we got a 10/10 score.

Mail server is set with utf-8 as the default.

As another test, I changed the email that is sent from HTML to TEXT and still found that the message received with hotmail.com had the strangely inserted symbols, which also made the confirm email link not work.

As for red text, none of our emails contains red text. I only highlighted the weirdly inserted symbols with red to make them easier to be seen in my forum post.

Has Joomlapolis never had an issue with users that have Microsoft email addresses?

It looks like entirely a UTF-8 encoding problem. Have you checked the headers within the raw email source data? Click the 3 dot menu when viewing the email in outlook then under View click View message source. You should find Content-Type in the source and should be set to text/html; charset=utf-8. This assumes you're not providing your own HTML email structure as CB won't set its own (which defaults to utf- unless overridden (if email begins with <html or <!DOCTYPE html> it will override CB).