Kindly let me whether vCenter IP Address is reachable.

hi john ,

which version of Vcenter do you used ?

you must used FQDN instead of ip for reach vcenter Web page .

and are you access to port 443 ??

Hi Muakhtar,

Yes I am able to ping the IP address. But I am not able to access the GUI

I am using version 7 and yes port 443 is enabled.

I was able to access it few days ago without any issues.

ping is not enough ,, 

you must ping FQDN name and Telnet IP 443 , 

if you can access in past it could be Certificate issue and maybe certificate expired. 

pls check certificate

Now I am trying to access the https://IPAddress:5480

And I am getting this issue: 

500 - Internal Server Error

Check the disk usage with df -h via SSH and try to start the services manually.

Start all services: service-control --start --all

 You can check the logs of the services that won't start to have an indication. Location : /storage/log/VMware/"service"/"service.log"

check if the certificates are still valid:

vCenter Appliance: Run the following command in a console window or SSH session to the vCenter VM:

for store in $(/usr/lib/vmware-vmafd/bin/vecs-cli store list | grep -v TRUSTED_ROOT_CRLS); do echo "[*] Store :" $store; /usr/lib/vmware-vmafd/bin/vecs-cli entry list --store $store --text | grep -ie "Alias" -ie "Not After";done;

vmware KB :>> https://kb.vmware.com/s/article/2015600

I am trying to open the Vcenter VM but it is showing DCUI aborted by exception. 

I am trying to access it using putty but it is saying connection refured.

"DCUI aborted by exception" . that sounds the the Photos OS vCSA has root partition full. 

Reboot vCSA VM and check once. "/" cleanup might be needed.

Hi @Ajay1988 ,

Thank you for that. Would it be ok to force restart the VM? As I can't connect via ssh and can't even open the browser.

Yes..Force restart the vCSA VM from ESXi. 

If you are able to access VAMI:5480 so check which service has been started and which one is not. 
you will be able to check all partitions.

Hi @Ajay1988 ,

Thanks for your help. After I forced restart the VM, it works as normal after that. It just took a long for it to run all the services and able to access on a browser.