@Duvy - I wouldn't try calling; they are not answering over 80% of the time due to heavy understaffing. and for security, I would doubt an agent is going to confirm or deny anything about a PIN, as it has the potential to compromise the security.
suggest determining if you ever set up a PIN for her (and this site will tell you what it is)
https://www.irs.gov/identity-theft-fraud-scams/get-an-identity-protection-pin
if you can't figure it out, as noted above, you'll need to paper file.
the PINs have nothing to do with being overseas nor whether she was or wasn't your dependent previously.
