The USPTO recently updated its database of Private PAIR users. The update has created difficulty for many users who have tried to access Private PAIR since the update.
If you are experiencing difficulty logging in to Private PAIR, here are the steps that the USPTO advised me to take in order to access the system:
- Delete your saved temporary Internet files and cookies. (To do this in Internet Explorer, select “Tools” at the top of the browser, then select and “Internet Options”)
- Close your browser, then re-open it.
- If you have PAIR bookmarked as a favorite, delete that favorite and find PAIR again using www.uspto.gov. Save the new address for the PAIR login page as a favorite. (The direct link is https://sportal.uspto.gov/secure/myportal/privatepair)
You should now be able to log in. This fix worked for me. Hopefully it will work for you, too. (And maybe this information will save you a phone call to USPTO technical support.)
IP Spotlight 
OUtstanding! Going to PAIR from the home page is what did the trick for me. Who would have thunk it?
exremely difficult to even find private pair
still doesnt work