Anyone know ,why is interface at ether 4 port warning ?
I plugged AG-HP-2G20 at ether 4 port wit AP Router mode.
it may harmful to mikrotik router and how can I solved it?
Thanks 
You need to check that the interface is running the same on both sides and that your patch lead is not faulty. This happens when one side of the connection is running at half-duplex and the other side is running at full-duplex.