Error uploading keeps loading

If your board doers not have the CH340 TTL-to-USB converter, you can run the loopback test. If you don't know if your board uses the CH340, you can find VID/PID in Windows device manager (properties->details tab->hardware ids) and look it up on e.g. All USB Vendors | Device Hunt (or google it).

Was this the first time that you used this board? Or was it working previously?
If the latter, what is the project that you last worked on or were working on before it failed the upload.