TL-MR6400 keeps restarting when certain device is connected through Ethernet
Hello.
I manage three (so far) solar parks of decent (1GWp each) size. I am using a TL-MR6400 4G router for connectivity on each one of them. Had no problems until today, that is until I tried to connect the ABB REF615 relays on the internet through the routers. Upon connecting the relay units onto any of the routers' ethernet ports, the routers go into restart-frenzy and power cycle continuously. Seems like it is a software issue, since the MR6400 restart after their startup process has been completed. The relays connect fine to the field laptop and I can access their web interface with no issues.
I have tried anything I could think of, swapped the power bricks, tested new cables, tried all ports, no other devices, even turned off WiFi. No change. A few seconds after the relay units connect to the routers, the routers start power-cycling every 30 seconds or so. All three routers. On all three parks. On all three ABB relay units. There is no record whatsoever on the routers' log file of the reset events, whatsoever. All routers are on different 4G carriers.
Any ideas?