ADTRAN Express 4120 - Manual (Page 171)

Appendix B. Log Messages
61200176L3-1 Express 4110/4120 User Manual B-21
TFTP: error rcvd - <message>"
level 2
Received error with <message> from TFTP server.
TFTP: lost communication
level 2
Lost communication to TFTP client or server during transfer.
TFTP server: unable to open port
level 2
TFTP server function could not open a UDP port.