Hi,

After every download, when the CPU switches from STOP to RUN, I get a Security Key Authentication Error. The error disappears after I reset the CPU and also after power off/power on. The program runs fine after that.

I've checked in the project -> security -> Security Key Management and Setting window, if there are any keys present in the CPU which may cause this error but there's no key registered on the CPU nor on the programs. We never used this feature.

Special about the setup: FX5U CPU 64 MR/DS in production, (on my desk 80 MR/DS) with a FX5_CNV_BUS and an FX3u_CAN module attached. For the CAN communication I'm using the function blocks provided by on the mitsubishi website (iQ-F - GX Works3 - CANopen - MEU+FX5UCPU_FX3UCANopen_00B).

I've tried not calling those blocks by commenting out some of them but the problem just appears after every download or reappears after a second/third download when nothing in the code significantly changed.

It's just inconvenient to reset the CPU after every download, so any help and ideas are greatly appreciated.