Why this proccess freezes at 99%?

Hello everyone, I'm new here.

I have a problem within the transaction "LTMC" in SAP4/HANA, I leave you a screenshot with the error message:

("Validate data" step is running in the background (99% complete)

It turns out that I need to upload files within a "migration project", but the previous upload I did, was frozen at 99% where it then stayed in the background, making it impossible to upload new files within this "migration project".

My question is, is there a way to stop this background process? Could it be a problem with the new account I use to do this upload process?

I am totally attentive to your comments, since I have been having this problem for a while and I cannot find a solution.

Thank you :).