We need more info to help out. What is shown when you click on a host on the monitor tab? To check connectivity between NSX hosts you can ssh to them and vmkping between their vmk10 IPs to check connectivity and MTU.
Also note that the tunnels are only tested when workloads are attached to them. Just preparing them does not trigger tunnel status check.
I had a similar issue, but that was only when i upgraded NSX-v from 6.2 to 6.4, i had to remove and re-add to fix the service.
When it says tunnels, does it mean the vTEPs, if so, see if you can VMKPING the vTEP from one host to another ensure the service is there.
I've not had much exposure to NSX-T, all my experience is NSX-V
This doesn't help. Did you see my first answer? Does vmkping work? How is it show on monitor for each transport node? Have you attached VMs to an overlay segment on each host? This is necessary to trigger tunnel check packets.
Try using vmkping to test the TEP connectivity and attached some VM to LS and then check the same.
Thanks. It worked.