vCenter upgrade - Stage 1 deployment validation failed due to VAMI is NOT accessible ETIMEOUT

[loclong1]

I am trying to upgrade vCenter from 6.5 to 7.0 U3c and it failed at the end of stage 1 during deployment validation.

The error in the installer log

"Could not get response for get request from url https://<temp ip>:5480. Error: connect ETIMEOUT <temp ip>:5480"

I have tried several temp ip addresses and did the upgrade with different target hosts but they all failed.

Doesn't appear to be DNS as both vCenter and Esxi could resolve their IP/FQDN.  I could access the current vCenter Appliance@5480 without issue.

The firewall on the Windows Server used for deployment is OFF.

Any ideas what might be blocking VAMI?

[maksym007]

Might be a certificate issue. 

Or as another solution make an upgrade to 6.7 U3 and after to 7.0.3

[loclong1]

I figured it out, The vlan configured for vcenter-recovery port group on the vDS was incorrect. It was changed from the original deployment but was not updated for recovery. The new vCenter cannot be reached on the wrong vlan hence VAMI is not accessible. The error in the installer log led me off a tangent as I thought something specific to port 5480 and firewalling/filtering issue.  However, the message on the GUI gave me a clue as it said "you could continue with the upgrade by logging in the new vCenter";  Since I cannot even ping the new VM , I started looking into networking/routing issues and discovered the vlan/subnet configuration problem.

Anyhow after changing the vlan to the correct one, it got past the validation and continued with the upgrade successfully