Resetting embed code will do the following.
Existing embeds will be disabled
Documents you've already embedded will be automatically disabled and you will not be able to enable them again.
A new embed code will be generated
A new embed code will be created and you will be able to use it to showcase the document.
Re-embed the document
Copy the embed code as highlighted in the example image and place it where your existing embed code was placed and you’re good to go.