Ensure you have the latest version of the Maxon App installed. Older versions often "hang" on expired license states even if a new trial period has been authorized for your account. 3. Educational and Lite Versions: The Permanent Trial

Maxon allows (for a small fee). You can buy a used perpetual license of Cinema 4D (versions up to R25 were perpetual) on eBay or Reddit forums (r/3Dmodeling).