Trello Doesn't Authenticate when Integrated

I've tried several times to authorize my account in Trello. Yet every time I go to fill a form, it says I first need to authorize my account. Logged out of both and back in; still no luck. I'm starting with a free Jotform account. Do I need to have a paid account fo integration?

You don't need to have a paid subscription to use JotForm's Integrations.

I have tested the Trello integration using my sample form and I was able to Integrate without any issue.

Can you please try to disable any pop-up blockers in your web browser?

Can you please try clearing your browser's cache or use another web browser in editing your form?

Can you try re-integrating your form with Trello?

When you click Authenticate in your Integration, make sure you allow JotForm to use your account.

Looking forward for your response.