sorry... this is your own mail server, as such you would need to do the leg work.
that said from ...
https://spamrl.com/
"
If your message was wrongly rejected, please try to find other means to each out to the recipient so they can
release & train the email from their spam quarantine and report your wrongly classified email to their antispam provider. This will not only resolve the immediate reputation issue, but also helps in improving your IP/domain reputation for the future. Although it was rejected with a 5xx error at SMTP level, they really can still access and release & train the email from their quarantine.
As you may not be able to get hold of the recipient immediately, as an immediate solution you can simply exclude your IP/domain with bad reputation for up to 7 days via this website. That should provide sufficient time for the recipient(s) to release & train your email from their spam quarantine, to resolve the reputation issue.
Unfortunately, there is no other way to improve your reputation, except by ensuring the recipient(s) report the mistake. We cannot manually resolve your reputation issues on this system; it's a fully automated process."
so the only options appear to be are to contact the affected recipient or wait for 7 days and try again.
thanks
sandy