inbox encryption - unsuported properties

hello!

Around 3 months ago I moved from old plan to new Light subscription plan - I was forced doing so as old plan wasn't supported anymore.
From the beginning (on old plan) I setup inbox encryption with my PGP public key - everything was working correctly and emails were encrypted. I'm not sure if moving to new plan is relevant information, but I couldn't find any other reason and hint why it could stop working.

Today I noticed that rule responsible for Inbox Encryption says: "This rule contains unsupported properties."

I was trying to update my public key, but nothing helped. After few tries and tinkering I started to get errors in UI (at the end of this post).

It's really disturbing that I didn't get any notification that emails are no longer encrypted in Inbox and also it's not understandable for me what has changed that my public key, which was working before without any issues, stopped working without warning.

Please help me to figure out what happened. I would like to use the same key as before.

Error during updating PGP public key:


Please review your mail filter rules as they seem to be invalid. Response from server: "Open-Xchange: line 63: error: pgp_encrypt command: invalid ASCII armor for key 1/369776464: premature end of header. Open-Xchange: error: validation failed. " (ID: 403901689-11521475 / MAIL_FILTER-0025) 6/26/2024 11:43 PM

/appsuite/api/mailfilter/v2?action=update&session=4f9f1122b1d14819a621aa47509a8900

PS.
You can download my PGP key from https://keys.openpgp.org/