hi guys,
I have a reliance netconnect+ usb modem(ZTE-AC2737) that works on windows and linux.I have been using it without any problem for the last 1 month.For the last couple of days ,when I try to connect,I get these messages on its gui

writing AT command to modem
waiting modem response
logging to net
not root user
kill PPP daemon
network disconnected

Sometimes it would connect with no problems.But sometimes this problem occurrs.It runs on windows without any glitch.

any idea how I can solve this?

thanks
sajan