If ertificate of Vcenter is expired, services are not starting and you cannot access your VCenter \\
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Connect to your Vcenter using SSH and verify status of certificates 
<cli>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;</cli>
Check all certificates and see if some are expired \\
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If you have expired certificates, use the certificate manager utility to automatically renew your certificates 
<cli>/usr/lib/vmware-vmca/bin/certificate-manager</cli>
Chose in the menu the option to renew required certificate \\