I had the same issue for months. Everytime I tried to apply it would take me to a screen that said I wasn't eligible to apply. I had never had a Paypal credit account (Comenity)or BML account before. Only thing I had was a Business Debit Card with them. Thinking that the Debit Card might be the issue, I cancelled it and tried applying again. Same results. I finally called Paypal Credit and told them I was concerned with the fact that their system would not even let me apply for a credit account, stating I wasn't eligible. I asked why and what exactly would make me ineligible. I told them I didn't mind being declined for a legitimate credit related reason but the blanket you can't apply didn't work for me. The representative was baffled. She did something, don't know what, but when that conversation ended I tried again and was able to access the application form, submit it and was approved. I have never had an issue since then and a couple months later was even approved for the Synchrony Paypal 2% Mastercard. I honestly think it was some type of "glitch" in their (Comenity)system that the representative overrode.
