Amy Hi, welcome to the forum.
I've recently had a firmware update: it was the firmware on the wifi dongle that links the inverter to your router, and then onto the portal. If you had the same update, and it went wrong for some reason, the dongle may be in the wrong state, and unable to connect. You won't be able send it any commands from the portal or app until it's resolved.
Probably best to get in touch with GE support, but they're possibly closed for the day/weekend, which is unfortunate timing. (Why push firmware updates on Fridays ?)
The good news is that the inverter will (probably) continue operate normally. You just can't change any settings in the mean time. A remote restart wouldn't work. I don't know if a full power cycle of the inverter (including batteries) would be any use.
To help, we'd need to know what sort of system you have - what hardware, generation, etc. How to access the dongle depends on that. On some systems, the dongle is visible, on others its hidden inside the casing. I don't know if you can simply unplug and replug the dongle while the inverter is running. (Not something I've ever had to worry about - hopefully someone who knows what they're talking about will come along soon.)