Welcome to the forum. Recent Roon updates (to version 2.65) increased the requirements for the operating system of the machine that is running Roon Server.
Hi @uilkema, welcome to the community. Since Roon is not starting at all on your Synology DS218+, the first thing we need to confirm is whether that NAS is running a DSM version that’s supported by the current Roon Server build.
Recent Roon updates raised the minimum operating system requirements for Roon Server on NAS devices, so please tell us which DSM version you are on. If you are not sure, Synology’s steps for checking it are here: How to check DSM version on Synology NAS.
Also let us know whether you were running Roon Server directly on the NAS or through Docker, and what happens when you try to start it, for example whether the service never appears, quits immediately, or shows an error.
Once we have that, we can point you to the right next step.