Hello! I see you're having trouble logging into the Nagad app and are looking for a permanent solution. To help you best, could you please share a bit more detail?

- What exactly happens when you try to log in? (e.g., error message, app freezes, OTP not received)
- Have you tried any fixes already? (like resetting your PIN, reinstalling the app)
- Is your device connected steadily to the internet?
- Do you use the latest version of the Nagad app on your Android 15 device?

With this info, I can guide you step-by-step to resolve this. Meanwhile, here are some common, effective steps that often solve login problems:

1. Check for App Updates: Ensure you have the latest Nagad app version from the Play Store. Developers regularly fix bugs that could cause login issues.

2. Clear App Cache & Data:
- Go to your device's Settings > Apps > Nagad > Storage.
- Tap 'Clear Cache' first, try to login again. If still no success, try 'Clear Data' (you may need to re-enter your info).

3. Reset Your Nagad PIN: If password or PIN might be the issue, use the 'Forgot PIN?' option in the app or visit Nagad PIN reset page to reset your PIN yourself.

4. Check Network Connection: Switch between Wi-Fi and mobile data to confirm stable internet access.

5. Device Lock or Security Settings: Sometimes device lock or security apps interfere. Make sure no security setting is blocking the app.

6. Reinstall the App: Uninstalling and reinstalling can fix corrupted app files.

Please try these first and tell me if any step solved your issue or if any errors appear. If login problems persist, I can assist with more advanced troubleshooting or escalate it.

Are you satisfied with the steps so far? Let me know!