You cannot add or modify subscriptions or services until the outstanding balance is paid. You should be able to do so in your Billing page. (Code: 1323)
What is the issue you’re encountering
when i chose free plan then they show me this error but not continue my website on cloudflare
all invices are paid but i still face error when i submit this website am just still grap in setup issue i cannot have option for a site that i remove from cloudflare
If you login at dash.cloudflare.com, select Support → Contact Cloudflare → Select Billing from the drop down. Follow the form top to bottom and at the bottom, indicate you need to open a ticket. Let us know if that does not work out for you.