KB: Resolve ERR_TOO_MANY_REDIRECTS connecting to Workspace
Solution Details
If the suggestion to "Try deleting your cookies" as indicated in the message does not help, removing the user from the Workspace and adding them back in resolves the issue of too many redirects when trying to connect to your Workspace.
Or
Go to the Altium365 Workspace members page, click on this user, then Remove, then use the Invite workspace button to Add the email to invite them again.
They will need to sign out, reopen the browser window and then sign in again.
Please note: if the user has previously released a project or placed a comment, once they are removed they will lose the ownership of the items (meaning it won't show that they are the owner of those items anymore) but those items will remain in the Altium 365 Workspace, and won't be deleted.
If that doesn't help, have them go to Preferences > Data Management > Servers > expand the Known Servers item > then click the "Clear Cache" control at the lower right of that (the servers section) panel to see if that makes any difference. If the Workspace shows up on that page, they can also make sure it is set to ON.