StackOverflow blocking new accounts creation with mailbox.org domain

Andres Diaz shared this problem ago

In Progress

I have tried to create an account with one of my @mailbox.org email accounts, however their services doesn't allow me to create such accounts, I tried with one of my aliases, and it still did not work, when reaching the support this was their response

"Hello,

Thanks for reaching out. The email address you’re attempting to use is being blocked by our security systems. Please try creating an account with a new email address.

Let us know if you run into the same issue (and what the new address used was) so we can investigate further.

Thanks,

Stack Exchange Community Support Team"

Are they deribetely blocking mailbox.org emails from account creation at StackOverflow?