To start, please make sure your Internet connection works well. If you are using a cellular connection, you might want to consider connecting to Wi-Fi.
Next, try clearing your cache. Go to the Settings of your phone > Tap on General > iPhone Storage > Select the Muscle Booster app > Tap Offload App.
If clearing the cache doesn’t help, please restart your device or reinstall the app by following the next steps:
1. Delete the app.
2. Download it again.
3. Open the app and tap on the I Already Have An Account button on the app’s opening screen.
If the issue persists or you need further assistance, reach out to our support team via the Contact Us form.