The DNS server can not resolve domain names or is not reachable.

because of a bad WiFi strength you do not get an IP address assigned or the DHCP server is misconfigured.

The symbol indicates, that WiFi calling is enabled The WiFi is activated and connected to a WiFi network. There's no SIM card attached to the device or the device could not recognize the SIM card correctly. The device is connected to another mobile network, but not to the one of your operator, and uses Roamind. because the network operator does not have coverage in this area or the SIM card is deactivated. The device currently is not connected to a mobile network, e.g. This symbol indicates, that the device is currently connected to a mobile network and visualizes the strength of the signal (relative as bars).

4G and LTE are used as synonyms, it depends on the devices branding, what is shown. The mobile data is enabled and the device is currently in the LTE/ 4G network. The mobile data is enabled and the device is currently in the GPRS network. The device is set to silent mode and will not emit any notification sounds. Visualizes that the device volume is set to 'vibrate only'.

The icons visible in this list can differ depending of the manufacturer and device, as well as the installed ROM however, in general they should, at least, look similar to each other or are completely the same. The following list will give you an overwview of some of these icons and their meanings, as well as what app generates them (if they're created by an app). Especially when using a new Android device, after Software updates or the installation of a new app, it's possible that you recognize new symbols or signs in the notification bar from which you don't know the meaning, yet.

Cell phone icon