For some reason, the Pitney-Bowes label address (pb.com) wasn' resolving for you at the time - there is no work around for that. Could be a PB.com server issue, or a DNS issue somewhere long the line.
You could try the "open the label window" link at the top if it happens again. Unlikely to work (if a DNS or server issue would fail the same), but it's free to try.
Yes you can print labels at PayPal when needed. You can print them from the PayPal eBAy transaction (but that may no longer be an option when you have an already purchased eBay label as above - tracking probably already uploaded to PayPal and "print label" option disappears).
https://www.paypal.com/us/cgi-bin/webscr?cmd=_ship-now or
https://www.paypal.com/shiplabel/create/You will have to manually enter the info, and will receive USPS Commercial pricing (same as eBay but no Comm+ if TRS). Can't print FedEx from PayPal. Tracking usually automatically uploads to eBay, but best to check.
