I was reviewing uceprotect policies a couple of hours ago and what you say is really strange.

Uce level 3 should never be used alone to block general tcp traffic.

Are you saying that Orange is using uce level 3 to block email sent from your DO vm? Are you really sure that Orange blocks for this list only? Is it possible that your ip is on another RBL?

If Orange is really blocking smtp based only on uce level 3 they are doing wrong: their system may be mis-configured or they have not read correctly hiw level 3 is populated.

Or - probably - they did on pourpose!

Today I checked september smtp traffic: almost 99% of traffic coming from uce level 1 (single ips) was spam. Traffic hitting level 2 but not present in level 1 (subnets, one I checked was /15!!) was also 99% spam.

Of the 5000k messages received, very few arrived into the mailboxes. A lot of messages were blocked by following spam checks and the few remaining were flagged as spam.

I feel your pain. If you host on DO and you send email, you should look for a email provider that will funnel your emails.

Ps: i repeat, email shoild not be bloocked only by uce level 3