Authenticating free 3 month Apple TV trial on LG TV

I saw this issue and I was having the same problems

"Hi.

I have a 3 month free trial of Apple TV with my LG Smart TV, I follow the online QR prompts to log in on my phone, the tv screen then accepts my Apple ID and I follow the other prompts on the TV, at the end it says 'Authentication required, continue on your smart phone, iPad or tablet to complete the process' but where do I look for this option as nothing opens up automatically on the phone I did the original QR prompt with and if I hit the continue button on the TV I get 'Purchase or Rental Not Complete, wait a moment and try again'??

I've opened up my Apple ID in my iTunes settings account on my laptop and can see I have 'made a purchase' today for £0 but if I try and watch something on the TV it takes me back to the 'sign up for 3 months' button so I'm just in an endless loop!

I've never had Apple TV on any device before so I know it's not that, it's how I authenticate it that is the issue! Help!"

The best fix was

"So someone found the bug, what you do is turn off AirPlay:

Go into Home Dashboard -> Airplay -> Settings -> AirPlay Off.

Then go back to tv+ and signing up will work."

I didn't have an IOS device so my solution was to change the payment method in my apple ID settings to Paypal and then I was able to sign up for the LG 3 month trial. Hope this helps someone