Trying to register for nest.pijul, email could not be sent

Question
1

I would like to try out pijul and migrate my setup repo from git to it.

Since I want to save it somewhere remote, I tried to make an account here: https://nest.pijul.com

But I used an E-Mail alias from addy.io, something like: pijul@abcd.addy.io

And got this error:

The email could not be sent. Please check the address, and try again later.

The mail is valid (used it to make this forum account), aliases are probably disabled for spamming reasons, is it somehow possible to allow mine? or what should I do?

2

It seems like the same issue as: Unable to sign up to the Pijul Nest

And the issue is not the mail alias, it is probably the mail server, because I also tried it with a proton mail.