I have tried to sign up with bubble.io today and had an issue with the signup form, saying my email wasn’t a valid email. Weird so I raised this to support and after a bit of back and forth this is the reply:

“Hello,

We just received word from our email verification service that [email protected]* is considered a privacy email, as it uses FastMail as a provider, which offers email masking services. Though we aren't able to safelist [email protected]* as a result of that information, an email address through a service like Outlook or Gmail, or other popular providers should not be stopped by our system, if you have access to one.

Apologies for the limited action we can take! Let us know if you have any further questions.”

* actual email redacted.

Seems they have some problems with “bad actors” creating accounts on their free plan for phishing/scam/illegal activity and have employed some email verification service to prevent this.

Seems like a bit of a joke that I can create a gmail account in a matter of minutes and be up and running.