It's quite challenging to document every possible case for when embedding might not be working as there are lots of possible reasons, but there are some things we've found to be common issues and have a few recommendations that might help.
Check if you added the embed code correctly to the page.
Exceptions apply for embedding forms on Squarespace.
Check that you are using the right embed code for what you want to do.
There are various options for embedding, including inline, popups, full screen, oEmbeds, and others.
If you have done everything laid out in our embedding documentation, including the recommendations above, and are still having issues, contact us at firstname.lastname@example.org or through the chat on our website. We'll help figure out what's going on and get you up and running!