Hello, I am new to Limesurvery. 
I wanted to edit the email template at the admin panel. But after I saved it, it keeps returning to the default template if I return from another page or refresh. The attached image is the error displayed at console. What should I check for this issue? Thank you very much.

You have not answered the basic questions at the beginning when starting a new post.

What is your LS version? Where / by whom is it hosted?