I can’t access anything apple on my phone when connected to one WiFi but when i connect to cellular or a different WiFi it works. I can’t play iTunes, go to iCloud.com, App Store, nothing.

If the Wi-Fi network is internal to a business or school, check with the IT group.

If not…

Check for firmware updates for and then restart the Wi-Fi router. Try again.

Forget the Wi-Fi network in Settings > Wi-Fi, force-restart the iPhone, and re-add the Wi-Fi network. Try again.

Then—if other devices are having issues on that same Wi-Fi—check with the ISP providing the internet connection.

Reset Network Settings: Only network settings are removed.

• When you reset network settings, previously used networks and VPN settings that weren’t installed by a configuration profile or mobile device management (MDM) are removed. Wi-Fi is turned off and then back on, disconnecting you from any network you’re on. The Wi-Fi and Ask to Join Networks settings remain turned on.
• To remove VPN settings installed by a configuration profile, go to Settings > General > Profiles & Device Management, select the configuration profile, then tap Remove Profile. This also removes other settings and accounts provided by the profile. See Install or remove configuration profiles on iPhone in this guide.
• To remove network settings installed by MDM, go to Settings > General > Profiles & Device Management, select the management, then tap Remove Management. This also removes other settings and certificates provided by MDM. See “Mobile device management (MDM)” in the iOS Deployment Reference.
• Reset your Network Settings. Tap Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

If the above fails...

Reset All Settings: All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.

1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
2. You can return settings to their defaults without erasing your content.
3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.

When troubleshooting connectivity issues with your iPhone and a Wi-Fi network, one possible explanation could be that the router has blocked your iPhone's MAC address or is configured to only allow specific MAC addresses to access the Wi-Fi network. Let's explore this further.

Every device that connects to a network has a unique identifier called a MAC address (Media Access Control address). This address is assigned to the network interface card (NIC) of the device, in this case, your iPhone. The MAC address is used by the router to identify and allow or block devices from accessing the network.

In some cases, the router's security settings may be configured to block certain MAC addresses from accessing the Wi-Fi network. This could be due to security concerns or the desire to restrict access to specific devices. If your iPhone's MAC address is blocked, it would prevent your device from connecting to the Wi-Fi network.

Alternatively, the router may have a whitelist feature enabled, which allows only specific MAC addresses to connect to the network. This feature is often used to enhance network security by restricting access to authorized devices. If your iPhone's MAC address is not included in the whitelist, you won't be able to connect to the Wi-Fi network.

To resolve this issue, you can try the following steps:

1. First, check if other devices can connect to the Wi-Fi network. If other devices are working fine, it suggests that the issue may be specific to your iPhone.
2. Verify the MAC address of your iPhone. You can find this information in the settings of your iPhone. Go to "Settings" > "General" > "About" > "Wi-Fi Address" (or "Ethernet Address" for some models). Make sure the MAC address matches the one you provided to the router.
3. Power cycling the router can sometimes resolve temporary issues. Turn off the router, wait for a few seconds, and then turn it back on. This action can help clear any temporary glitches or conflicts.
4. Access the router's configuration page through a web browser. Consult the router's manual or manufacturer's website for instructions on how to access the settings. Look for any MAC address filtering or whitelist settings. If you find any MAC address filtering options, ensure that your iPhone's MAC address is not blocked. If there is a whitelist, add your iPhone's MAC address to the allowed list.
5. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
6. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
7. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)
8. Contact your network administrator: If you're connecting to a Wi-Fi network in a corporate or educational environment, it's possible that the network administrator has intentionally restricted access for specific MAC addresses. In such cases, reach out to the network administrator or IT department for further assistance.

By following these steps, you should be able to determine if your iPhone's MAC address is blocked or if there are specific MAC address restrictions in place on the router. Remember to consult the router's manual or contact the manufacturer for specific instructions related to your router model.

Did you check the wi-fi network with your provider to see if there's anything wrong with it

That would tend to imply that the problem lies with the specific WiFi network you’re connected to.