A frequent question I am asked about LinkedIn is "How do I check the status of my invitations? Were they really sent?
The two page doc included here takes you through the steps:
LinkedIn - How do I check the status of my Invitations?
Basically, you sign into your LinkedIn account. Go to your Inbox. The default position shows your sent messages. Change the view to show your Sent Invitations. You can now view each one individually and 15 at a time, page by page.
If an invitation has not been accepted in over three months, I usually resend (or at least check on the email address before resending). If after a re-send, and then more time, the invitation is still not accepted, I would withdraw the invitation. As this point you know only that the person is not active on LinkedIn and wouldn't be much help to you unless they were.
How do you handle aging invitations?
Note: email subscribers will need to click through to view the document.