Hi @Mojgan, I'm sorry for the inconvenience but I inform you that there are no disservices reported. The described criticality is certainly attributable to a temporary network congestion. In these cases we suggest a network switch: enter your device's settings and switch the network from 4G to 2G (3G if it's an iPhone), wait for the E to appear and turn off the device for a few minutes. Turn it back on, wait for the E to reappear and switch the network back to 4G. The switch and shutdown (not restart) of the smartphone involve the acquisition of a new priority on the cell and a consequent improvement in the quality of the network. I am available.