Can you not set any breakpoints at all, or is it just at this particular location?
A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
In the attached screenshot there are two main files open, so make sure that the code where you are trying to set the breakpoint is actually being executed. Also check that compiler optimisations are off in Project > Properties > C/C++ Build > Settings > Tool Settings > MCU GCC Compiler > Debugging by setting its level to -O0.
Check if the breakpoint has a condition that will never be met. You can, also, run Clean and Rebuild.