There’ve been certain features/updates over the years for which client and server version dependencies were created. Version 7.4 (from 2022) of the Apple TV client, for example, was the last to support server versions earlier than 1.15.2:
The same is true for other clients. The server version you’re using is nearly 7 years old and hundreds of versions out-of-date. It is neither viable as a server for modern clients nor is it any longer secure (there have been several vulnerabilities addressed in the intervening years).