We're having problems with some routers in the field where the is link / no link issues happening. Upon reboot of the router that fixes the issue, although we cannot find what is causing it. Auto negotiate is also enabled on the interface ports. Any ideas as to what might be causing this? So far two routers that this is happening on is at 6.17....

Go to the interface you see this on using winbox and have a look at the RX Stats tab.
Are there FCS errors?
If so check cables, Ends, Arrestors, POEs, etc.
Try gently cleaning the pins and wires on Ethernet ports and ends with a BURNISHING BRUSH.
If all else fails try a new ethernet port.

Go to the interface you see this on using winbox and have a look at the RX Stats tab.
Are there FCS errors?
If so check cables, Ends, Arrestors, POEs, etc.
Try gently cleaning the pins and wires on Ethernet ports and ends with a BURNISHING BRUSH.
If all else fails try a new ethernet port.

It seems to be happening with this firmware only though or so far that I can tell.... We're also using 3rd party boxes and not ones directly from Mikrotik.

Can happen on Tik, Cisco, UBNT, Brocade, etc.

Can happen on Tik, Cisco, UBNT, Brocade, etc.

What do you mean by that? So should we be cleaning the ports like you mentioned?

Anyone else have an idea? Upgraded to 6.20 and still happening about 7-10 days after upgrade.....

I'm having this or a similar problem on a CCR2004. I'm connecting several individuals of the same electronics card directly to the CCR2004. It is a hit and miss situation. Often it works, but too often it does not. In some cases the link has gone up after 10-20 minutes if left connected (but not always).

All individuals, all of them with no exception, will connect immediately to any other device, router or switch - Except for the Mikrotik device.

Different ports in the CCR2004 and/or different cables makes no difference.

Edit:
I know this is an old thread, but I found no newer ones on this topic.