VMware vCenter - Alarm Network uplink redundancy lost

had similar issues as far as the network speed dropping to 10 or 100. First thing is that I make sure both sides are set to Auto if it's 1 GB links. Second, is that I have our hardware team reseat the cabling all the way back to the switch. 9/10 times that has resolved it. The root cause is usually the cabling was a little loose, not snapped all the way in, or the cable was bent forcing a pin or two to lose contact with the port.

In a few rare cases they were due to bad patch cables.

This may not be good for you since you only have 2 ports, but on our servers I've also modified the host profile to fail a port if the link speed is below 999MB, that way it forces all of the traffic over to the other port without dropping speed as the switches try to renegotiate.

Lost power or temporary power shortage on the network could also caused alarm Network uplink redundancy lost issue. Acknowledge and  reset to Green on Alarm messages.