Can you try? Just to make sure it's not a browser problem.
Did you try in XCP-ng Center?
This would help narrow down the problem.
@LEB-ID It's called Add new Server in XCP-ng Center too... old habits die hard. But Pools is not the right word either. It's hard coming up with something short and precise.
@LEB-ID Yes, in XO > Settings > Servers should only have a single entry.
XO > Home > Hosts should display your 2 servers
How many Pools do you have? How many Hosts?
If you have 1 XCP-ng Pool, you only need 1 entry in your XO Servers page, the master only.