To resolve the "Login error. A security measure" issue on the SecureSafe Password Manager app for your iPhone 14 Pro, follow these actionable steps:

1. Check Your Internet Connection: Ensure that your device has a stable internet connection. An unstable or nonexistent connection can disrupt the login process.

2. Reconfirm Login Credentials: Double-check that you are entering the correct username and password. Any typing errors or incorrect details will lead to login errors. If uncertain, consider resetting your password as follows:
- Open the SecureSafe app.
- Click on "Forgot your password?" and follow the prompts to reset it.

3. Account Lock Check: If you’ve attempted to log in unsuccessfully more than 10 times, your account may be temporarily locked for security reasons. This lock lasts for 30 minutes. Wait for this duration and try again - learn more.

4. App Permissions: Ensure that your app has the necessary permissions enabled:
- Go to your device's Settings.
- Scroll down to find SecureSafe and check its permissions, such as access to the network.

5. Update the App: Check for updates to the SecureSafe app. An outdated version may have bugs or compatibility issues:
- Open the App Store.
- Search for SecureSafe and check if an update is available. Install it if necessary - learn more.

6. Enable Touch ID/Face ID: If you are using biometric login (Touch ID or Face ID), ensure it is enabled in both the app and within your device settings:
- Inside the SecureSafe app, navigate to Settings and enable Touch ID or Face ID if it’s not already.
- Go to Settings on your iPhone, then tap on Face ID & Passcode or Touch ID & Passcode to ensure they are set up correctly - learn more.

7. Clear App Cache: If issues persist, try clearing the app’s cache or data:
- Uninstall the app and then reinstall it. This may help in resolving any internal glitches.

8. Contact Support: If you've followed the above steps and are still facing the login issue, consider reaching out to SecureSafe customer support for further assistance.

By thoroughly following these steps, you should be able to troubleshoot and resolve the login issue with your SecureSafe Password Manager app on your iPhone 14 Pro effectively.