Hi Yana thanks for posting in the Lucid Community! Sorry for the trouble with inserting your document - I'd be happy to help!

• Would you mind connecting to a different network to rule out any connection issues?
• Could you also try opening the Google Doc/Slide/Sheet in an incognito window to rule out browser interference?
• If you remove the diagram and then reinsert it does that resolve the issue?
• If you uninstall and reinstall the add-on are you able to insert your document successfully? Please note that if the Lucidchart Add-on has been deployed by your admin you will be unable to uninstall it.

If the issue persists, please respond with the following information so we can take a closer look:

• A document support PIN for the document you’re attempting to insert via the add-on. Note that this PIN is for internal use only and won’t grant public access to your document, so you can share it directly in this thread. 
• A screenshot of the associated Javascript Console output after reproducing the issue. You can open your Javascript Console by pressing Ctrl + Shift + J (if your computer is a Windows / Linux) OR Cmd + Opt + J (if your computer is a Mac).