Can too many rejections of similars cause closing my account?

Yes.

But you need to spam the database with similar pictures already submitted in your portfolio. As for the other refections (for similar): You submitted a topic that is overwhelmingly saturated and your pictures are not spectacular enough, to add your “me too bird” to the database. You should avoid those topics in the future.

Thank you all for your helpfull comments

Always compare your work with current inventory to see if Adobe Stock needs any more of those.  If they have 24 million of those that look like yours, it's a safe bet they don't need any more. Hence, duplicaet content. 

LIkewise, ensure that what you submit is as good or better than what Stock has.  They're very choosy about what they accept now and for good reason.  Stock contains over 300 million assets.

Hope that helps.

An account can get suspended that has a low acceptance rate though, although I don't know what that threshold is.  I seem to remember an overall rate of 50%, but I'm not sure where I saw that.

From what I've seen in this regard, there is a lot of room for trial and error for those who submit in good faith in my opinion.

I think it's important to remember that we aren't Adobe employees, and there for we can only speculate about exactly how the Adobe Stock Contributor team will handle situations.  Some things are spelled out, others haven't been publicly commented on so we just don't know.  From what I've seen though, there is a lot of room given to contributors who are submitting in good faith and attempting to follow the guidelines.

I believe this is spelled out in the Similar Images vs Spam portion of the Adobe Stock Contributor User Guide.  It's worth a read if you haven't done so already.

"Sending multiple copies of identical content can be perceived as image spam, and can result in your account being blocked or permanently closed."

Adobe can close b the account at any time that thenTerms of Agreement are violated. Spamming is one reason.

So the answer is "yes".