Quote from: GazetaBitcoin on April 05, 2025, 12:27:22 PM

And, of course, I received an email from Mailer Daemon, saying the email was not sent... I hope though it was sent to the other address. I also added eXch in Bcc. Let's hope for the best...

I have noticed one thing with ProtonMail is that when you create an account, then you have to do some verification, I think phone number of alternative email address before you're allowed to receive emails, from some websites, even after doing that I've faced problems with some emails getting received, Till now I haven't used Protonmail for sending emails.

Few hours ago I did sent an email to 'david.k@ocpt.cd' (I hope that's the email you're referring to for not being able to send to). Till now I haven't received any email of it's failure of being sent, can you check if you get this error from alternative email service, like Gmail... (Edit: It was not sent from Protonmail).

I can't pinpoint the exact reason for it, but some users have made some reasonable statements about it,

Quote from: NotATether on March 27, 2025, 02:51:48 PM

That's Proton Mail blocking your message from being sent. Have you used this email for anything else before? They really don't like it when you only send outgoing messages. Especially if you are a free account.

Quote from: eXch Support on March 27, 2025, 11:28:23 AM

Hello Cricktor

It seems the spam filter in question is Proton Mail's itself, not ours. Proton Mail sometimes rejects outgoing emails for suspecting it might be a spam that their user sends.

I took a break while writing this post and sent an email to 'david.k@ocpt.cd' from Gmail. It worked, but no reply of 'it's failure' was received. ~~It's likely a problem with ProtonMail.~~

Just received an email from 'Mailer-Daemon'

Code:

<david.k@ocpt.cd>: Host or domain name not found. Name service error for
name=ocpt.cd type=MX: Host not found, try again

It's an invalid email address. - More details on this email