This error indicates that the HOSTID linked to your up.time your Uptime Infrastructure Monitor license key does not match the HOSTID of your current monitoring station.
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Regardless of the root cause, you will need to generate a new license key that matches the new HOSTID (How to Find Your HOSTID). You can do this by logging into the uptime Uptime licensing portal, expand the Deployment Name and click on Re-host License Key.