“Not In Service Area. Network Failure.” Is Displayed; Standby Time Declines - Maxcom MM41D User Manual

"Not in service area. Network failure." is displayed
Check signal intensity indicator. If there is no signal, you
may be in the basement or network blind area in a
building. Please move to another location to receive
signal. If in your situation you are not covered by a
network, please contact your operator for details.
Poor sound quality, echo or noise makes
communication difficult.
Hang-up your phone and dial again. Your network may
connect the phone to a line with better communication
quality.

Standby time declines

Signal at your location is weak, making the phone search
for signal for a long time. When you don't want to answer
any calls, please turn off your phone's power for a time
being to help preserve battery life. It is also possible that
the battery has been used for a long time and is
approaching its life-span. In this case, please replace the
battery.