Redgate Monitor has reverted to a trial after upgrading to version 12

When upgrading from any major version prior to version 12 (e.g. upgrading from 10-12) you'll find that your licenses have deactivated and are no longer visible on the licensing page. This behavior is intended so the license server can check that your license is compatible with version 12 when you reactivate. You may also see this message after updating:

In order to start monitoring your servers you will need to activate a license that is within its support contract. You can easily check this by logging in to the account license section of the customer portal. Here you will be able to see if the license is supported and if you're entitled to use the latest version with your license.
Go to Licenses, click on Redgate Monitor in your product list, go to Tools included and click on the tile to expand. 

A window will open to the right hand side of your screen where the version number is shown: 

Licenses are backwards compatible, so you can use your license with any versions up to the version number shown. 

If you're unable to see any Redgate Monitor licenses in your portal please reach out to support to help locate your license(s).

Once you've verified that your licenses are valid for version 12 or above, you can move on to activating the license. If you're not aware, a change was made in Redgate Monitor 11.2.3 that updated the license activation mechanic, so now you no longer need to activate using the serial key. Please see the guide below on how to activate using the new method:

How to activate your Redgate Monitor licenses (versions 11.2.3 and later) RECOMMENDED

If your Redgate Monitor installation doesn't have a connection to the license server (e.g. if you're in a locked down environment without internet access) then please see the guide below on activating using the offline method:

How to activate and deactivate your Redgate Monitor licenses when you are not connected to the internet (version 11.2.14 and later) .