My issue is the application appears on the service page and then disappears
There is a time range in the top right corner. If your application stops sending data for a long time it will not appear in the list. It’s not really about the docker if you could get some data.
SigNoz is an open-source APM. It helps developers monitor their applications & troubleshoot problems, an open-source alternative to DataDog, NewRelic, etc.