InfoPath Dev

I have 2 sub sites, lets call them sub site A and sub site B, in my SharePoint 2013. I have published an Infopath form to Sub Site A and it is in use for the last 3 months. Now when I want to add another from to sub site A or to sub site B, I get the above error. What could have changed that I suddenly can not access the lists through InfoPath, and how can I resovle this?

Yuck. Have you tried from a different machine?

Yes thank you. Turned out both accounts I used to log in was locked for some reason - very strange, but luckily the problem was not to big.