Oops! Something went wrong and We couldn't initialize a part of your form correctly.

Suddenly i cannot edit  all my forms either create a new form. It gaves me the error message (see screenshot link below) 

http://prnt.sc/emayaj

In addition to this, this is only happened when i used v4. but when i change the platform to v3, form is working properly. any thoughts?

Hi, thank you for contacting us.

Please note that we were aware of the issue and our developers have already addressed it. Please try again and get back to us if the problem persists.

Apologies for the inconvenience.