Hi,
Try this 3 things will solve your problem.
- Log in to the vCenter Server and try restarting the VMware VirtualCenter Server Service. After the service is restarted, try to log in again.
- Try logging in to vCenter Server with another user to check if the behavior is specific to the user that has been added.If it is, add the appropriate permissions to the user's account that is not able to log in. You can add the permissions by selecting an object from the inventory and clicking the Permissions tab. On the Permissions tab, right-click and select Add Permission to add permissions for the user.
- Try logging in with the local administrator account on the vCenter Server. If it is, add the appropriate permissions for the user that is not able to log in by selecting an object from the inventory and clicking the Permissions tab. On the Permissions tab right click and select Add Permission to add permissions for the user.