They can only be accessed from the Google Drive link in Course Navigation.
You may also need to confirm any Google extensions installed in your browser's settings. Confirm the account you are using for each location and try again. Back up all of your content to the cloud easily access your files in Google Drive and your photos in Google Photos. If you want to enable Quick Access, select the checkbox beside Suggestions. If you are able to log in with the incognito browser, you are most likely logged in to Google Drive and/or Canvas with different Google accounts. In the Settings pop-up, you will see Suggestions.
The Google Drive folder is accessed from the Course Navigation Menu. If your course has enabled Google Apps, you can view all files in your Google Drive account in Canvas.