Skype call instantly says "busy" after 1 or 2 seconds. Help? (see details)?

[Numsies]

Okay so lately skype calls would just drop and say "busy" after one or two seconds, but the thing is this only happens for one of my contacts. My calls work completely fine for anyone else but for this one friend it says busy. It also states that she's online 24/7. I can call her and see when she's off or online whenever on my phone, or even call her in a group chat. Solutions?
She is able to call me just fine, I think.

[justme]

If it's working with everyone else, that suggests that the problem may be at her end. Have you talked to her about the problem? Maybe she needs to check her settings.