I have a solution.Documentation says:DBGMCU registersThe DBGMCU registers are not reset by a system reset, only by a power-on reset. They areaccessible to the debugger via the AHB access port at base address 0xE004 4000.DBGMCU configuration register ...

The issue was in the level of the PAx pin. It should be the same as VCC. Check your level by multimeter.