if your Solis WiFi Data Logger is having issues such as not connecting to the local network or not providing the "AP" (Access Point) network required for configuration, resetting it to factory default could be the fix that you need.
To reset it to factory default settings, the procedure will depends on which version of the Solis WiFi Data Logger that you have. This article is for the older version, photo below:
If you take the case off and you can find a button like so circled in red-
Hold it down for 5 seconds. Note: the logger needs to be connected to a powered-on inverter.
If that button isn't there, then you have the earliest model and you will need to short the two pins circled in red. Do this by using a small piece of wire or a paper clip to touch the two points together for 5 seconds, this will reset it (again, do this while the logger is connected to a powered on inverter so that the lights are on).