Hi @farhan.ali7 please can you specify vCD version and if you use SAML or other type of authentication.
I think your issue appear when, frmo vCD you click on More - Data Protection….. correct? Have you tried to connect on the Veeam enterprise manager portal with same credentials?
Thanks
What do you have configured for the hostname in vCD?
e.g. Login to vCD as a provider admin > More Data Protection with Veeam
I just went through this with our testing. It has to do with CORS and having a different domain for our vCloud since it can have a public URL and then our VEM/VBK server having an internal domain. You need to edit a config file for VEM to put the public domain for vCloud there and restart the VEM service and also the IIS website (reboot the server if you can instead). This will then fix it.
This is the line to edit - Program Files\Veeam\Backup and Replication\Enterprise Manager\WebApp\web.config
The line you need to change is this one - <add key="security-headers:vcdIpOrDnsAddress" value="https://vcloudurl.domain.com/" />