Project could not save - Scratch

Problem: The Project could not save prompt appears in the Scratch 3.0 online editor when a project failed to save to the website.

Next to the prompt, there are two buttons. The project will retry to be saved when Try again is clicked, and when Download is clicked the project will be downloaded as an sb3 file.

Solution: Open a new tab and check that you are signed into the right account. If not, sign in.