You can upload files for email verification one by one. This means that you can only upload one file at once. However, there is no limit to how many files you can upload. You have to upload them one after the other.
By default 2 uploaded files will be running simultaneously/ in parallel. If you have more than 2 new files uploaded, 2 will run, and the others will stay in a queue. As soon as one file finishes another will start verifying. Currently, it is not possible to change the number of running files in the verification process.
