Have this configuration 2 hEX S routers (RB760iGS firmware 6.47) , are connected by a SFP copper cable S+DA0001 (disabled Auto Negotiation, 1 GB Full Duplex). A pretty typical configuration, the first router has the public addresses, the second one DHCP and the private ones, both have a public IP. On the second router on eth 5 is a TPLink AP (ddWRT) running on POE (disabled Auto Negotiation, 100 MPS, forced on).
This used to work. 2 days ago was a power outage, all is on UPS but after half an hour the computers shut down and rest remained on as long as the batteries still had juice.
After when the power kick back in, the first sign was the AP was turned off, did a couple of power cycles and nothing. Tried to power from the first router port 5, still nothing. Did MAC resets on the interface and so, still nothing. The AP is OK, since I put a power injector and works as before. Did double check if running on latest versions of firmware on the routers, rebooted all and so and nothing.
In the process discovered that the SFP communication between routers is off. Reseted the second router to factory defaults restored the configuration back, cold booted bot routers with SFP module in, changed in the second router in WinBox Quick Set to SFP1 did all the steps (of course the Ethernet cable in port 1 taken out). Tried 1 GB, 10 GB speeds still nothing. Always the SFP interface at cable test say No Link. As before all these tries.
The configuration now works with an Ethernet cable between routers (SFP is still physically connected), and AP on power injector... Is not quite optimal....
Any idea how to troubleshoot these issues? Have no idea where to look anymore.