Recently, many partners have reported issues with Dynamics 365 Business Central on-premises customers following their license upgrades. The problem, which comes up after user login, seems to be prevalent and under-recognized.
The issue stems from a new requirement introduced in October 2022 mandating all apps in a Dynamics 365 Business Central environment to adhere to the Universal Code initiative. This is designed to promote the use of modern architecture in customer implementations. New on-premises customers and those transitioning to Dynamics 365 Business Central on-premises deployments must deploy a "cloud-optimized extensions" architecture (Universal Code) or license payable modules that enable traditional customization behavior.
In practical terms, extensions should not have target = onPrem in the app.json file. If they do, one or both of the following modules need to be licensed in the customer’s license:
Dynamics 365 Business Central: Universal Code and Microsoft’s apps problems. – Stefano Demiliani