
The cause seems to be that when you upgrade to iOS 15.2 or higher, the Safari setting ``Prevent cross-site tracking'' is turned on.
▶Change settings
Home screen → "Settings" → "Safari" → "Privacy and Security" → Disable "Prevent cross-site tracking".
*Please turn it off at your own risk.
▶Change browser
Browse using a browser other than Safari.
▶View the calendar directly
Irodori's Google Calendar