Hi,
The message typically indicates that the debugger stopped in a fault handler or at an invalid address where no source code is available. Please try a clean rebuild, power-cycle the board, and restart the debug session. Also verify that the correct *.elf file is selected in the GDB PEMicro debug configuration.
Additionally, please test whether the issue can be reproduced with a standard NXP S32K144 example project. This will help determine if the problem is application-specific.
Please also check which update level of S32 Design Studio for ARM 2018.R1 you currently have installed. If you are not using Update 11 (or newer), we recommend applying the update, as it contains fixes and SDK updates for S32K1xx devices.
BR, Petr