Hi there! I understand that you're having trouble connecting the SOLARMAN Smart app to Wi-Fi while it works fine on mobile data. That can be frustrating! Let's try to resolve this together.

To start, could you let me know if you've made any recent changes to your Wi-Fi network, such as a new password, or if you recently changed your router? It would also be helpful to know if you're getting any specific error messages when trying to connect via Wi-Fi.

In the meantime, here are a few steps we can try:

1. Check Wi-Fi Connection: Make sure that your phone is connected to the correct Wi-Fi network. Sometimes, devices get linked to a different network by mistake.

2. Wi-Fi Settings: Open the SOLARMAN Smart app and ensure that it has the necessary permissions to use Wi-Fi. You can check your phone settings to confirm this.

3. Router Settings: Some routers may have settings that restrict devices from connecting. If possible, check that the 2.4 GHz band is enabled on your router, as many smart devices use that frequency.

4. Restart Devices: Try restarting both your phone and the Wi-Fi router. Sometimes, just a quick reboot can help the devices reconnect.

5. Reconfigure the App: If the above steps don't work, you may need to reconfigure the SOLARMAN app. This may involve connecting the app to the Wi-Fi again by going through the setup process as detailed in the user manual or guide.

If these steps don't help, we may need to dive a bit deeper into your settings or confirm that there aren’t any issues with your Wi-Fi connection itself. Please let me know how it goes or if you have any additional details!