iPhone and iPad default cookies settings are set to Allow from Websites I Visit, which prevents third-party cookies from being saved on your system. To enable third-party cookies:
Step 1: On your iPhone or iPad, go to Settings.
Step 2: Select Safari.
Step 3: Under Privacy & Security, toggle off Block All Cookies and Prevent Cross-Site Tracking.
Step 4: You may need to restart Safari for the new settings to take effect.