Hey. I can not activate Studio CE. What is the reason and how to fix it?
You need to renew license here.
In case you already used enterprise edition You cannot go back to Community Edition after activating a license key on a machine. It contravenes with CE terms and conditions. After you have once activated a device with a license code in the past you cannot use the free edition on the same device. After code activation, the device ID remains registered in the system and it does not allow you to go back and activate CE.
In special situations where the above should be approved (going to Community after using a trial or license key) you will need to reach out to support and give details on your request and also provide the device ID of the machine. If the request is approved, support will release the device ID from the system and it will be possible to activate CE.