To fix the issue of recent calls not showing on iPhone, you can try the following solutions:

1/ Force restart your iPhone by holding down the power and home buttons (or volume down button for iPhone 7 and later) until you see the Apple logo.

2/ Reset the date and time on your iPhone by going to Settings > General > Date & Time and turning on Set Automatically.

3/ Check your call settings by going to Settings > Phone and making sure that Show Recent Calls is turned on.

4/ Check your iPhone storage by going to Settings > General > iPhone Storage and deleting any unwanted apps or files.

5/ Reset your network settings by going to Settings > General > Reset > Reset Network Settings.