Cannot install or retrieve license key

We have about 8 VPS servers that are recently failing to install or update their license keys.
When we try to update the key it hangs for about 15 minutes and then fails with 504 gateway timeout.

We can ping ka.odin.com and it resolves to the correct ips etc. from each server.
Reboots don't seem to help and neither does installing the license from a file.

Any advice would be appreciated.
Thanks