I discovered the printer arbitrarily changed its IP Address (the last octet only) and no longer matched what the computer had stored. I installed another Pro-300 printer in the computer using the new IP Address, and everything worked fine again. I ...
Same problem with Pro-300 and M1 iMac (Big Sur), running as standalone. Worked a week ago. Now when I send file from PP&L to printer I immediately get an error message in Print Queue Window telling me to check printer's operation panel or Remote UI...
