Can't debug a project


I’ve been using my STM32L053 DISCOVERY board for a few months. It worked until yesterday. I wrote a program to write a 4 char array to eeprom, under my lecturers supervision, and suddenly my and four of my student mates boards “crashed“ during debugging session. I am using KeilV5.28.0.0 version, toolchain is MDK-ARM Cortex-M0/M0+ 256K.

Those are the errors that we are getting:
E310  : Debug access failed - cannot read address 0xF0000FE4 (accsize ‘4’, AP ‘0’)
Error: Flash download failed - Target DLL has been cancelled

We tried reinstalling the drivers and restarting our computers. We also tried reflashing firmware with STM32CubePrg, changed debug connecting settings in project options - neither of the above works to solve our problem.

Anyone has any ideas how to solve this?

Adding a picture of the errors I am getting:

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