If for some reason that you or your users are unable to access the the user portal on the Safari web browser on a Mac OS, please do the following:
Go to
Safari PreferenceClick on the
Privacy tabUncheck
Prevent cross-site tracking to disable thisClick on the
Developer tabCheck on
Disable cross-origin restrictionsOnce the above steps are done, log out and re-login back to the portal and try accessing the user portal again and this time the page should load.

Safari Privacy settings tab with "Prevent cross-site tracking" checkbox highlighted by a green arrow

Safari Developer settings with "Disable cross-origin restrictions" checkbox enabled under Security