☆ After configuration, the yellow led blinks twice regularly within 1.6 sec.

Please try follow steps to fix the issue:

1. Restart inverter;
2. Connect to Solar-WiFi and login again, check the 'SD', 'Security Mode', 'Encryption Type' and 'Pass Phrase' is matching with that of Wi-Fi router or not;
3. Connect to Wi-FI router and login to check if the connection reaches the maximum amount or not, and to check the channel of it uses.Please make sure the channel is not bigger than 13. Otherwise, modify it;
4. Restart Wi-Fi router ;
5. Move Wi-Fi router closer to inverter or use a Wi-Fi repeater device.