Cannot create account/sign in with Google account on iOS

Cannot create account/sign in with Google account on iOS

I just discovered Notebook and love the idea of it. I downloaded the Mac version successfully and logged in with my google account. I tried to do the same thing with my iPhone, but it gave me a 403 error: disallowed_useragent. I'd like to link to my google account with my phone so both devices are synced. Help please.