you for reaching out to the Community regarding your issue, although I am sorry
to hear that you are experiencing issues with entering your transaction. That quite odd that it keeps giving you back and forth errors. I'm wondering here if we might be able to fix the issue by changing the security then reverting it back.
To do this you'll want to go across the top to tools > security list. Find the security you're having issues with and open it. From here you should have the security overview open and on the left you'll want to click edit details. we'll want to change it to a different security. It doesn't matter which one as long as you don't own it. Click ok then update. It should bring in information on the stock so it should be changed. From there you should be able to do the same process but instead look up the original stick and update it.
Once you've done this see if you're still having the same error as before. Please let us know what you find.