Can't connect to printer

All of a sudden Cura can’t connect to my printer. I am using current version of software, 3.6.20. Have a Mini 1 with the micro .25 nozzle. And when it was working it ran very slow. So slow that filament would come out in spurts. A half hour before this happened it printed seven small parts just fine. Removed the parts, cleaned the bed and start the next small parts.
The tech had me reinstall the software and then the firmware when it was running very slow. So then he told me to do it again. Then it wouldn’t even connect. I have Simplify 3D but don’t use it yet. However, it couldn’t connect either.
I have had nothing but trouble with this printer. Really thinking I need to buy a different brand.

Can you share any screenshots or specific error messages? It could be a number of things, but one possibility that comes to mind is that (iirc) with one firmware update the baud rate changed from 115200 to 250000. Manually specifying the port and baud rate might help. If it has the newest firmware flashed, the baud rate should be 250000.