As of CF2023 Update 24, the CF Admin Log Viewer is throwing a "Error Occurred While Processing Request Complex object types cannot be converted to simple values." error when attempting the view a log.

Running into the same issue. Based on the bug tracker, they were able to reproduce the issue so hoping to see a fix soon.

Not sure if you created this ticket https://tracker.adobe.com/#/view/CF-4234708
But it’s verified bug, and it’s not solved on update 25 nor on update 26 so we wait I guess…

I tried to purge felix caches and reinstall administrator package and to rollback to update 25 but issue persists and to be honest I did not try to rollback to update 24 and older ones.

I hope you can access the instance installation directory and check log files there :) 

Same thing happening on CF Update 26

Not all logs thou, we can open coldfusion-out.log, coldfusion-error.log and exception.log rest of logs produce this error