To keep you signed in as you move around the site, Scratch uses cookies: small pieces of data we give to your browser. If you find that you become signed out right after signing in, you should check to make sure that cookies are enabled.

If you have disabled cookies you won't be able to remain signed in. Here's how to ensure that cookies are enabled for a few common web browsers:

Chrome: In a new tab, enter this into your URL bar: chrome://settings/. Then choose "Privacy and Security" and choose "Cookies and other site data."  Make sure you are not blocking cookies or that you add to the "Sites that can always use cookies" section.

Firefox: Choose the three line menu in the upper right and choose "Preferences" from the dropdown. Choose "Privacy and Security" and scroll down to the "Cookies and Site Data" section. Click "Manage Permissions" and make sure that is allowed to use cookies.

Safari: In the Safari menu, choose "Preferences". Choose "Privacy" from the list at the top of the window. Under "Cookies and Website Data", make sure that "Block all cookies" is not selected.

Edge: Select the 3 dot menu in the upper right of the browser and choose "Settings."  Select "Site Permissions" and choose "Cookies and site data."  Make sure that either "Allow sites to save and read cookie data" is turned on, or add to the "Allow" list.