I recently put 2 C5c radios in PTP, the problem is that I cannot access their web interface, version 2.8.1 was installed at the time of activation, the link is working perfectly but I cannot access through static IP, so no way.
Are they using DHCP or static IPs?
Try scanning the network to see which IP addresses are in use. It may be that their addresses were mistyped. Can you ping them? Are they passing traffic between each other (i.e. do you have communication with a device on the other side of the radios)? Did you set the Management VLAN setting? Do they show up in the Mimosa Cloud?