Please check whether there are any firewall rules or proxy settings.
Ive created a new firewall rule > WAN >TCP/UDP> Source Port (any) > Destination (VCSA IP address) > dest. port (443 & 80), same results.
However, if I try to access VMware Appliance Management ipaddress:5480, it seems to be working fine there.
Do you think this is a problem with DNS?
The error message says "IP address could not be found", so yes, please check for proper name resolution.
Are you able to access the UI by IP address, i.e. similar to accessing the Management page?
Also - as mentioned in the first reply - make sure that the URL is not redirected by a proxy setting.
Check the following:
1. you should do DNS name resolution successfully: When you want to open with FQDN, the client must resolve the VCSA IP address
2. Try to open VAMI: http://VCSA_IP_ADDR:5480 and if you could check all the services status
3. Check the firewall settings of your web client's system. (or even antivirus built-in firewall, if you have)
4. Change your browser and check the system proxy settings
5. Check time setting of the client system and vCenter server.Please mark my comment as the Correct Answer if this solution resolved your problem