Are you using the “Add to Homescreen” approach?
Just brainstorming a bit of troubleshooting steps to help narrow down where the issue might be… have you tried:
- Closing all browser tabs that have SharpTools open in Safari (and swipe away the ‘Add to Homescreen’ version from your app switcher to close it), then try opening SharpTools directly in Safari
- Swipe away the ‘Add to Homescreen’ version from your app switcher to close it, then restart your iPhone, then try opening it again
- You mentioned WiFi, so have you tried (after the above steps) on Cellular instead of Wifi?