When are you getting that message? Is it during initial registration with LinkedIn or on a returning login visit? Also, is the avatar being pulled in properly? If so, it may just be an odd error message we need to look at... in which case, you can disable the "Show LinkedIn API Errors on Front-end" setting to hide that message for now.
To note, I just tried logging in, and I didn't get that message. My avatar did look to be updated though.