Back in 2014, I installed the Mobile Link monitor on my Generac 6244 20KW. It worked real well until Verizon began phasing out the CDMA cell phone service. From that point, the Mobile Link app displayed the generator as "not connected". I saw on this forum that some of the Generac techs were installing a booster antenna on units with this problem, to strengthen the signal. I researched the booster antenna and saw that it had a magnetic base. Since my generator housing is all aluminum as well as my deck railing nearby, I did not see this as a workable solution for me. So, I tried a different approach. I went on Amazon and ordered an SMA Male to SMA Female Bulkhead RG174 Cable. I found a narrow piece of sheet metal in my garage, drilled a hole in the sheet metal large enough for the bulkhead fitting to pass through, and secured the fitting with the nut. I attached the Mobile Link antenna to the fitting, got my step ladder, and slid the sheet metal holding the antenna under a roof shingle. I then routed the cable in the channel for the vinyl siding, along my deck rail, and connected it to the Mobile Link unit. The Mobile Link now works all the time. No more "not connected" when checking the app. I wanted to post this so if anyone else is having this issue, they may want to try this out. Attached are a couple of pics.

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Just so you know, Generac will be offering an upgrade for Mobil Link sometime late this year or early next year that will allow your unit to operate on Verizon 4G and 5G networks.
Verizon might have disabled CDMA equipment at the nearest cell site, or the soon-to-be-retired equipment could have failed, and they are letting a more distant site cover the area. The remote antenna is a good idea.

There are 2 types of boosters. One redirects the cell signal over the internet. The other picks up the cell signal from the phone or MobileLink and rebroadcasts from a roof antenna - and vice versa.