1) Did you try rebooting your router?
2) Is your WiFi name or password being changed recently? Please note that both WiFi Name and Password are case sensitive. Hope you have taken care of case sensitivity when configuring WiFi Name (SSID) and password.
Please call our support number (0) 8130345141 if rebooting router does not solve the issue and you are sure that you have configured properly taking care of case sensitivity during configuration.