@domi
Are you using the "4Relay module" or the "4Relay unit" or the "2Relay module" ?

If you still get an error, try to make a simple Uiflow programm scanning the i2c bus with the 4Relay connected:
0_1675006853542_cfe4a152-de11-4d5b-8158-f44191defe28-image.png
You should get the number [38, 117] displayed as Label0, 38 is the decimal for 0x26.
If you get 37 you have another firmware than I have (I2C address 0x25).
If you only get [117] your 4Relay module is not connected to the M5Stack core. 117 (0x75) is the I2C address of the battery management chip.