License assignment failure due to incorrect license server configuration in VCF 9.1

Products

VCF Operations VMware Cloud Foundation

Issue/Introduction

When attempting to assign licenses to a vCenter instance in VMware Cloud Foundation (VCF) 9.1, the operation fails with the following error:
```
Licenses could not be assigned to vCenter.
```

The /var/log/vmware/cis-license/license.log on the vCenter appliance shows below error:

ERROR CISLicense [vc@4413 threadName="http-nio-0.0.0.0-12080-exec-1"] Caught exception:
com.vmware.cis.license.entitlement.management.exception.LicenseServerManagementException: Failed to get Entitlements [...] from License Server [...] with URL [<wrong_FQDN>] with response [License Server connection error: java.net.SocketTimeoutException: Read timed out]
Failed to get Entitlements from License Server with URL [<wrong_FQDN>] with response [License Server connection error: java.net.SocketTimeoutException: Read timed out]
}],
    data = UpdateErrorInfo (com.vmware.cis.license.subscription.entitlement.entitlements.update_error_info) => {
        reason = LICENSE_SERVER_FAILURE
    },
    errorType = ERROR
}

In /storage/log/vcops/log/adapters/ManagementAdapter/ManagementAdapter_##.log of VCF Operations, the following error is recorded:

ERROR ManagementAdapter 6529 [ops@4413 threadId="65526" threadName="vcf-licensing-assign-19" instanceId="61"] [(61) com.vmware.adapter.management.components.licensing.vcf.EntitlementMutationManager.updateEntitlement]
- Task ########-####-####-####-############:com.vmware.cis.license.subscription.entitlement.entitlements failed to assigning entitlement ########-####-####-####-############, task details: Info (com.vmware.cis.task.info) => {
    progress = Progress (com.vmware.cis.task.progress) => {
        total = 100,
        completed = 100,
        message = LocalizableMessage (com.vmware.vapi.std.localizable_message) => {
            id = unused.id,
            defaultMessage = Task failed.,
            args = [],
            params = <null>,
            localized = Task failed.
        }
    },
    result = <null>,
    description = LocalizableMessage (com.vmware.vapi.std.localizable_message) => {
        id = unused.id,
        defaultMessage = Entitlement task,
        args = [],
        params = <null>,
        localized = Entitlement task
    },
    service = com.vmware.cis.license.subscription.entitlement.entitlements,
    operation = update,
    parent = <null>,
    target = <null>,
    status = FAILED,
    cancelable = false,
    error = Error (com.vmware.vapi.std.errors.error) => {
        messages = [LocalizableMessage (com.vmware.vapi.std.localizable_message) => {
    id = unused.id,
    defaultMessage = Failed to get Entitlements [########-####-####-####-############] from License Server [########-####-####-####-############] with URL [<wrong_licenseserver_fqdn>] with response [License Server connection error: java.net.SocketTimeoutException: Read timed out],
    args = [],
    params = <null>,
    localized = Failed to get Entitlements [########-####-####-####-############] from License Server [########-####-####-####-############] with URL [<wrong_licenseserver_fqdn>] with response [License Server connection error: java.net.SocketTimeoutException: Read timed out]
}],
        data = com.vmware.cis.license.subscription.entitlement.entitlements.update_error_info => {reason=LICENSE_SERVER_FAILURE},
        errorType = ERROR

When checking the license server console directly, the status displays as connected, but it shows an incorrect hostname.
Forward and reverse lookup from vCenter to the license server is valid

Environment

VCF Operations 9.1
VMware Cloud Foundation 9.1

Cause

This issue occurs because the license server was deployed with an incorrect domain name or FQDN during the initial installation. As a result, the vCenter attempts to reach the entitlement service using a malformed or unreachable URL, leading to a network timeout despite basic connectivity (nslookup) working correctly for the individual components.

Note: ICMP traffic is disabled in the current released version, but will be enabled in upcoming releases of the license server.

Resolution

Unregister the misconfigured license server from the environment and redeploy it utilizing the Fully Qualified Domain Name (FQDN) of the license server.

Take SSH session to the affected vCenter Server appliance using root credentials.
Validate that the Forward Lookup Zones (A records) and Reverse Lookup Zones (PTR records) for the license server.
```
nslookup <Target_License_Server_FQDN>
nslookup <Target_License_Server_IP>
```
Verify that all required network paths—specifically secure communication over TCP Port 443 are unrestricted across intervening security zones between the vCenter Server instances, VCF Operations, and the target License Server. Refer: Unable to license vCenter after upgrading to 9.1
If the hostname mismatch occurs, proceed with deleting the existing license sever. Follow the verified workflow sequence to explicitly disassociate and remove the faulty registration entity. For specific step-by-step UI actions, reference the official documentation: Remove a License Server.
Initiate the creation workflow for the license server, ensuring the complete Fully Qualified Domain Name (FQDN) is used during deployment.

Notes:
- In the network configuration fields, ensure to enter in the absolute Fully Qualified Domain Name (e.g., licenseserver.example.local) in the naming parameters rather than entering a standalone short hostname syntax.
- The entered hostname must be all lower-case. A single upper-case letter will cause a failed license assignment.
- Refer: Register VCF Operations
After completing the redeployment, you will be able to successfully assign the licenses to the vCenter Server instance.

Additional Information

The issue can also be caused due to vCenter Instance UUID case mismatch between vCenter and VCF Operations and the same can be confirmed by reviewing the VCF Operations and vCenter logs. See kb: Licenses could not be assigned to vCenters, license assignment failure on VCF 9.1 due to vCenter UUID case mismatch