"Cannot validate proxy configuration. Proxy server didn't allow connection from VCF SDDC Manager to destination URL"
"Can't validate proxy configuration. Destination test URL https://depot.vmware.com returned unexpected HTTP Status. Call VMWARE Support."
VCF 5.x
Caused, by a recent change of authentication method in broadcom depot dl.broadcom.com.
During proxy configuration, VCF SDDC Manager try to validate proxy configuration by using it to connect to dl.broadcom.com(depot.vmware.com) and expect specific HTTP Status codes as response. The depot hosting changed this code from 401 AuthRequired for unauthenticated connection to 403 Forbid or 404 Not found.
su -
/etc/vmware/vcf/operationsmanager/application.properties
proxy.configuration.validation.expected.http.statuses=401,403,404
proxy.configuration.validation.test.url=https://dl.broadcom.com
systemctl restart operationsmanager