After you change or remove the PIN online, try restarting your Roku device by performing a "System restart" under Settings->System or Settings->System->Power depending on your Roku device. Also, just in case you have multiple Roku devices you may have multiple Roku accounts, so make sure you're logging in using the email address that's displayed on your Roku device under Settings->System->About.
Roku Community Streaming Expert
Help others find this answer and click "Accept as Solution."
If you appreciate my answer, maybe give me a Kudo.
I am not a Roku employee.