Can't edit in v4

I tried to rename my form using the new editor, but in the middle of it, "something went wrong" and the page goes black. Now I can't get into any form to edit it or even select v3 instead—I'm basically locked out of editing altogether.

I'm using a Mac with 10.11.6 and Safari 10.

Thanks!

We bug that caused forms to not be editable in V4.  It has been fixed and you can now edit forms once again.  Apologies for the down time.