There is an expected situation when one can’t open a CODAP doc saved to Google Drive: When one account was used to save it and another account is used to open it. We’ve seen this with some people who have work and personal google accounts, even if both accounts should have the same access to the file. If one account was used to save and another account was attempting to open, it can cause an error. Not saying that is what is happening in this case, but might be an issue for some.