Problem with Arduino disconnect

Hello, i have a Little Problem with the connectivity of an arduino mega and blynk app.

My arduino and also the blynk app runs very good while app is online.
Only when the app is offline (that happens most of the day) my arduino hangs up while sending some virtual pin Status or any data (temperature, pressure, humidity o.e.) to the blynk Server.

My blynk communication is programmed as described in blynk Firmware. However it runs when app is online very good.

I dont know whats wrong - maybe a Memory Overflow?

Thanks for help.

Could you upload you code?