Canon 18-135 Lens, with adapter, Will Not Auto-Focus On My Canon EOS R Camera

[eapples]

Hello:  The auto-focus feature will not work when I attach my Canon 18-135 lens to my Canon EOS R camera.

I was using that lens on my Canon Rebel dSLR camera, and it worked perfectly.

My Canon 18-55 and my Tamron 70-300 work fine on the mirrorless camera.  I am using an adapter with all the lenses.  It's only the 18-135 that won't play nice with the mirrorless camera.

I'm content to use manual focus; but, using the auto-focus feature would make life a bit easier.

If you need more information to help me to resolve this dilemma, I will provide it ASAP.  Thank you in advance for your help.  AND I apologize if I've already raised this issue in this forum.

[deebatman316]

I would check the AF/MF switch and ensure it’s set to AF instead of MF. 

[eapples]

AF is my default setting.  I use MF mostly for close-ups.

Thanks again for your help.