If you're trying to sign in to Microsoft To Do on the web and see a 503 error, this could be related to limitations in the local network or restrictions on a corporate network.
Check with your IT admin to make sure none of these URLs are blocked:
-
.microsoft.com
-
.msecnd.net
-
.live.com
-
graph.windows.net
-
graph.microsoft.com
-
.office.com
-
.office.net
-
.office365.com
-
static2.sharepointonline.com
-
todo-web-endpoint.azureedge.net
-
.microsoftonline.com
-
.microsoft.io
-
.windows.net
-
microsoft-my.sharepoint.com
-
microsoft.sharepoint.com
-
login.microsoftonline.com
