My OUTGOING mail is getting blocked as spam?

Multiple times I have had issues with outbound email getting rejected by Comodo’s servers returning “550 High probability of spam”.

It is absolutely, 100% NOT spam. I have whitelisted the recipient as I was instructed to in the past by support, and this is not making any difference. I have an important email that needs to get sent, and I can’t send it. Why is this happening and how do I resolve it?

can you please provide us your domain and sender email address? We’ll check the case