If you are using Safari browser (default on Mac, iPhone, iPad), a recent change in the browser's default settings has caused problems.
There are a couple of options:
- If you must use the Safari web browser, please enable 3rdparty cookies. Open Safari > Preferences > Privacy and disable the checkbox called "Prevent cross-site tracking". Note that Safari 13.x may show slightly different text.
- Alternatively, use Firefox or Chrome as your browser
If you're still unable to log in, Can you please share a full screenshot of the browser window with the errors and rest of the screen visible?