Epson WorkForce Pro WF-7820 All-in-One Inkjet Printer - Manual (Page 313)

313
Code Condition/solution
206 The phone cable is incorrectly connected to the product's LINE and EXT ports. Connect
the phone cable correctly.
207 The phone cable is not connected. Connect the phone cable.
208 The fax could not be sent to some of the specified recipients.
Print a fax log to check which recipients failed to receive the fax. You may be able to
resend a fax from the Job Status menu.
301
401
There is not enough storage space available on the external memory device. Clear space
on the device or use a different device.
302
402
The external memory device is write-protected; disable write protection.
303 No folder is available for saving the scanned file. Create a folder or use a different
memory device.
304
404
The external memory device has been removed. Reinsert the device.
305
405
An error occurred while saving data to the external memory device.
306
315
327
The product's memory is full. Wait until other ongoing jobs are finished.
311
321
411
421
A DNS error has occurred. Check the DNS settings in the Network Settings menu.
312
322
412
An authentication error has occurred. Check the location or server settings in the Network
Settings menu.