Please review the following:
- Is the Wi-Fi connection in the 2.4GHz band?
- Are the Wi-Fi module type settings correct?
https://docs.neqto.com/docs/en/spresense-series/software/initial_setting_for_wifi#wi-fi-module-type-setting - Is WPA/WPA2 used as the authentication method?
- Is the MAC address retrievable using the wifi mac command?
Once the Wi-Fi connection settings are configured, enter the "start" command followed by the "wifi mac" command. If the MAC address cannot be retrieved, it may be that the Spresense main board and the Wi-Fi add-on board are not connected properly (may be the result of poor contact). - Please review the additional troubleshooting section.
https://docs.neqto.com/docs/en/spresense-series/software/initial_setting_for_wifi#troubleshooting