Check this out:
Hello. Today I notice that the Google autofil through my Google account not working anymore. Whet I try to write a username and a password I see the message "Contents can't be autofilled" Also I notice that in settings/Google/autofil/autofil with...
Watch the video that the user Shymmy posted just below that post.
Also, check this out, as well:
If those posts didn't help, check this out:
If the threads in the link above won't help, then you can look for a password manager on Play Store like LastPass, that also has autofill.
This is how you could enable autofill with a different service that you have installed: