Can't send or receive any e-mails, account disabled

Hello,

On 28 September 2026 my mailbox.org account suddenly stopped working. Incoming mail to my address and to my custom-domain alias bounced with "550 5.1.1 Recipient address rejected: User unknown in relay recipient table", and sending failed with "450 4.7.1 SASL login name rejected (7515)". Another account on the same custom domain still works normally, so the domain setup is fine.

On 27 September I sent one single email through the EasyDMARC deliverability test tool, which uses a list of about 100 seed addresses, to check the SPF, DKIM and DMARC setup of my own domain. I understand that this can look like bulk mailing to an automated system, and I will not do it again. However I want to emphasize that this is no spam in any way and I simply wanted to test if my DNS was set-up correctly. I have not knowingly sent anything else.

Support told me the account was used for mass-sending of fraudulent, phishing or spam emails, and that it has been disabled. I explained the test to them and asked for a review and a password reset, but I have not received an answer yet.

What I am asking:

1. A human review of the account logs. I believe they will show one test message and no phishing or spam campaign.

2. The reinstating of my account so I can send and receive e-mails again, which is important as I use this account for university and personal purposes.

Has anyone here had an account reinstated after an automatic block like this? Is there a better way to reach the abuse or account team than the normal support ticket?

Thank you.