EP06E loses connectivity every 24h or so

Hi, so I built a 4G router with the U7621-01 and I have installed a quectel EP06E mini pcie modem. It works really well, but I have noticed that every 24H approximately it loses the ip and therefore my connection. If I check the current settings it gives and "Out of call" error. My only solution right now is rebooting the router entirely, and it works fine after that. Any idea on how would I solve this issue?