Reading through your post again, I think we need more details…
By “Application Offline” do you mean the Blynk App is not logging in? Or the device in a particular project is not online?
If referring to the project, is it also running on the same RPI?
If so, what library (C++, NodeJS, Python)?
Do you have ANY projects that work?
Have you switched all clients over to port 8080 as required for Local Server now?
Read this for more info - New Blynk Library v0.5.1 is Released (important for local server owners)