Both you and the contact you send an IM too have to be online at the same time. Until you are, the message will stay pending, at least for a week or so until it times out.
06-11-2012 02:31 - edited 06-11-2012 02:35
I have an alternative explanation :
It means Skype does not work
Me and my daughter are both online at this very moment, we both have good internet connections thank you, we cannot call, I have sent her 5 messages in the last 10 minutes and they are all still pending
It is also shameful, because this is not free anymore. Actually I pay more money to Skype than I do to my phone company. As soon as I have time to investigate an alternative service, they will not see me again.
I'm having a similar issue using Skype credit to send SMS to a mobile phone and status says pending and he never gets SMS, but the credit is removed from my account balance.
SMS and IM problems are really not the same.
In the case of an SMS message not being delivered, the problem can be that the recipient's mobile provider blocks SMS messages from Skype. Or, if you don't have your caller ID setup, that provider may block messages that have no caller ID.
The person you're trying to SMS to should check with their mobile provider to see if Skype text messages are being blocked.
As soon as my messages were left in "Pending" I joked that the Chinese have intercepted all of Skype again.
It now is impossibe to send messages on a regular basis ( with confidence) and will have to resort to facebook messenger to keep up with the modern world.
I still think that Skype has been hacked which is bloody unfortunate.