I've had this happen when mods merged two or more threads by the same author, about the same project.
Go to the author, if you can find them, and look at what current threads they have. If you don't know who it was, well...
What subforum were you posting it in? There's a general electronics subforum, and I don't see why they'd squash it if it was over there. Usually, even if it isn't topical, it's allowed within reason, based on what I've seen. General Electronics
Upper right hand of your screen, do you have a "1" beside your "H" - if so, click on that, you might have a note from the mods about your post.
Don't know what mechanism took you off, but newbies have some severe restrictions. You need to read some posts and do some other stuff before your trust level gets upgraded, then you can post more than one item, etc. etc.
Here's how you solve that. You're at Trust Level 0. Please visit this page: New User Limits
As explained there, you need to do something to achieve Trust Level 1.
The forum's automated spam filter sometimes produces false positives, which result in those topics temporarily being hidden unjustly. This is why a team of human moderators review every action taken by the automated system.
So I think in the end these false detections are always corrected, but there is an unfortunate delay between the time of the spam detection and when a moderator reviews the action.
This has now happened and your topic has already been restored so you should be able to access it again.
Moving topics is for sure one action that can trigger it.
I can reply to an OP that the topic will be moved and next move it. After the move, the topic sometimes becomes "corrupt".
If I change the sequence to move followed by reply and it happens, I can't reply because the topic was (temporarily) hidden.
If there are already replies, the opening post disappears and the replies stay. Refreshing the page results in the OOPS page.