Lots of possiblities.
Do you have static address and are they in the correct format 192.168.0.1/24)?
Wireless Settings>Radio X> Basic. Mode and Channel the same on both radios?
Wireless Settings>Backhaul. Is Auto WDS Meshing enabled on both radios?
Wireless Settings>BSS>Security. Is the Mesh Network ID the same?
Wired settings>Ethernet>>VLAN>Access VLAN. Are they the same?
That should make it all work.