OPS manager issue with ping

Hello everyone, new member here, and in mongo world, in general.
I have an issue with Mongo OPS manager.
Configuration is 3 node cluster, 1 primary, 2 secondary, standard config. There was some activity by vendor done, i’m unable to get info about what was done exactly, since it’s Sunday, but all 3 nodes were rebooted.

Since then, OPS manager is showing the deployment status as red, as it’s unable to ping the machines anymore. Everything still works fine, agents are up, no alerts, etc, just that ping does not work, and also, when you go to servers view, it does not show the OS name, and RAM in the server details anymore.

My first thought is that it’s a firewall issue, some ports have been blocked, but the only info i found is that agents use the default mongo ops port to send data to ops manager.
I tried telnet from one of the machines to ops manager port, works fine, and then again, everything in ops manager works fine, except from ping/and details of the machine from OS side.

Any thoughts on this?