I sent messages to my friend on whatsapp & it shows only one tick mark?

[?]

I tried sending messages to my friend and whenever I used to send her messages earlier, it always used to show double tick mark beside messages. Also my friend used to reply immediately. But this time when I sent messages it was showing only one tick mark and haven't received reply from her. What does that mean? Does it mean she haven't read the messages yet that is why it is showing single tick mark or something else?

[Doom 3]

Hi

No Need to Worry .. Whatsapp Work on Server Bases Once u Send the Msg it will go to the service from there to ur Friend Mobile ... the Single Click Mark Many Be ur Friend is not using whatsapp any More Or he/She is not Connected with Internet .

Regards
Ali

[Rishad]

I can help u contact me…..
my viber whatap & wechat no +97477409042

[Syd]

it means ur frnd hasnt seen yo msg yet .