Flamingo caused forms can’t be filled out on the website

Our forms of contactform 7 do not load anymore. When someone fills out a form on our website the form keeps on buffering.

We have tried to deactivate and activate the plugin Flamingo. Only when the plugin Flamingo is deactivated forms can be filled out. If not: it keeps on buffering.

Is there a bug in Flamingo? Or is there something else we should try? So that we can use the plugin Flamingo again.