For some reason one of the forms is not saving anymore. So we can't edit it. Earlier it worked just fine. If we create a new form, we can edit and save. But this specific form won't anymore (earlier it did).
The form is a temporary solution for a webshop of a customer that is down at the moment. So it has dropdowns with a lot of products. But I guess this is not the problem, because earlier it saved just fine.
NOTE: We updated to the last version of GF, but it did not help.
PS: GF is great! We use it for a lot of our websites. Have not found any other WP plugin for forms that is so versatile and jet so simple.