EF 50mm f/1.8 STM Lens Generates "No Lens Attached" Error on EOS 77D

[ssantra]

Hello,

  I am using a Canon 77D. Yesterday, I bought a Canon 50 mm f/1.8 STM. But when I try to change the aperture it is giving me the message "cannot adjust aperture, No lens attached."  I  have no idea why this is happening. I have a canon EFS 55-250 mm lens, with which I can change the aperture and everything works fine. Please help. Thank you.

[MikeSowsun]

My 80D is my only camera with the lens retract feature. I also own the EF-S 24mm f/2.8 STM, EF 40mm f/2.8 STM, and EF 50mm f/1.8 STM. None of them cause an error if I remove the lens while the camera is on. 

Try using your 5D Mk IV with another STM lens, or try your EF 50mm f/1.8 STM on another camera with the lens retract feature. The error message should not happen just because you remove the lens with the power on. 

Can you show us a screenshot of the error message?

[deebatman316]

I doesn't always happen. But it happens every once in awhile. But after updating the camera's firmware I haven't seen it. But when it does happen it's says "Lens communication error".