Could not find symbol '00000013'

Hello, I have a very strange and annoying problem with my app. When I use the Eclipse emulator everything works fine. But I get an error message on my Garmin.

Error message from the CIQ_LOG.YML:

Error: Symbol Not Found Error
Details: "Could not find symbol '00000013'"
Time: 2021-04-04T21:02:20Z
Part-Number: 006-B2512-00
Firmware-Version: '5.90'
Language-Code: deu
ConnectIQ-Version: 3.2.3
Store-Id: 5e37bd85-f69f-405e-a75c-a78ef9be0d7c
Store-Version: 7
Filename: 73CC
Appname: Geocaching Lab
Stack:
  - pc: 0x10001e56
  - pc: 0x10001c33

How can I find out which symbol was not found? Can someone help me?