You likely can't fix the problem. In cases where vCenter has been installed using the IP address and not the fully-qualified host name, you cannot change its IP address. Doing so will, as you have discovered, break vCenter. Your best bet at this point is to deploy the vCSA on version 6.0 or higher and migrate your hosts over to it, or revert your vCenter if you have a snapshot or backup. vSphere 5.5 is EOGS in September of 2018, so now might seem like a good time to move away from it.
daphnissov, thank you!
But can I just reinstall vCenter and set the IP I need during installation ? If I decide to reinstall the vCenter what should I do with licence?
I have no VMware subscriptions, so I can't migrate to vCSA 6.x, as far as I know.
You can try these steps
1.Remove old IP from registry (windows vc/vm) you need to search 3-4 times in regedit.
2 Create forward and reverse lookup zone in DNS with new IP
3 restart DNS service
4.Flush DNS and register on VC/VM
5. Reboot VC and try to logon.
I had such cases several times and each time should reinstall vCenter from scratch.
I deployed VCSA and it solved the problem.