I just tried again with a shorter title (below) and still got the same error message.
“Reddit’s The_Donald Was One Of The Biggest Havens For Russian Propaganda“ (72 characters)
“Reddit’s The_Donald Was One Of The Biggest Havens For Russian Propaganda“ (72 characters)
AFAIK, if you're logged in and have a title that's of acceptable length, you should be able to submit. Any flagging or whatnot happens after submission: there's no filtering that happens before the submit button is clicked.
If you think something else is going on, or there's something that's affecting your account, I again suggest you contact the mods directly. If that is the case, they're the only ones who are going to be able to confirm and address it.
<guess> You probably submitted the story once and see that it was killed (automatically). Then you probably deleted it and tried to resubmit it (with a shorter and longer title) (from your account and from other account).
Probably some of the automatic spam filters can detect resubmission of deleted stories, perhaps for a short time. This is probably to prevent spammers form resubmitting stories that are flagged/killed. You are not a spammer, but automatic filters sometimes make mistakes.</guess>
In any case, to get an official reply, send an email to the mods.