To do this, the inverter must first be accessed using the FusionSolar app and a USB commissioning stick. After successfully logging in with the "extended user", the required APN data of the Internet provider can be entered in the main menu under:
Settings -> Communication Configuration -> 4G Communication
Now the commissioning stick can be exchanged with the 4G dongle.
Attention:
It is essential to remove the SIM PIN lock beforehand.