Odd, now it's back. This is what it was returning for a few minutes:

Just noticed Firefox complaining about a bad cert on LinkedIn:

# openssl s_client -showcerts -connect www.linkedin.com:443

CONNECTED(00000003)
depth=0 /C=US/ST=California/L=Mountain View/O=LinkedIn Corporation/CN=www.linkedin.com
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=LinkedIn Corporation/CN=www.linkedin.com
verify error:num=27:certificate not trusted
verify return:1
depth=0 /C=US/ST=California/L=Mountain View/O=LinkedIn Corporation/CN=www.linkedin.com
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/C=US/ST=California/L=Mountain View/O=LinkedIn Corporation/CN=www.linkedin.com
i:/C=US/O=DigiCert Inc/CN=DigiCert SHA2 Secure Server CA
-----BEGIN CERTIFICATE-----
MIIFKDCCBBCgAwIBAgIQDNq1J0qHKyBzE3L2tPlfFTANBgkqhkiG9w0BAQsFADBN
MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMScwJQYDVQQDEx5E
aWdpQ2VydCBTSEEyIFNlY3VyZSBTZXJ2ZXIgQ0EwHhcNMTMxMjIwMDAwMDAwWhcN
MTYxMjMwMTIwMDAwWjB0MQswCQYDVQQGEwJVUzETMBEGA1UECBMKQ2FsaWZvcm5p
YTEWMBQGA1UEBxMNTW91bnRhaW4gVmlldzEdMBsGA1UEChMUTGlua2VkSW4gQ29y
cG9yYXRpb24xGTAXBgNVBAMTEHd3dy5saW5rZWRpbi5jb20wggEiMA0GCSqGSIb3
DQEBAQUAA4IBDwAwggEKAoIBAQDonjtjfyzzJpMwPemr/7SILcI3tYASHCZFCYAj
cKilx5uzUQ3SbVy9c756arI7XHiMYYko01hr/+qSSJ/In1bu1hG1zx5BppF++OHS
ZT6dmtlmBXx1zOSp7rBkejXPXDBoQU6sRPhrh/6hiy3tmt/nvdLRJSFZzHhHUfAQ
hjdF9HBnpZt9ybPfg/Mgh91GM3MQBYqQr+NRvS5o64Vc0Hl+bCfTdwHKU8b61U0T
wvIlogZtr3XtiojKkiHspifDjVAqBN80CAUAe2FCIsjXDNl5gO+xpjKAWwGVs1fi
/JzcOZzoHrKhPNj7geF+I5dhQ2rK3g4RWgEGMjFCVxsXxdhFAgMBAAGjggHbMIIB
1zAfBgNVHSMEGDAWgBQPgGEcgjFh1S8o541GOLQs4cbZ4jAdBgNVHQ4EFgQUSdvg
SgTuENyanFYdq/abApsMrJIwKQYDVR0RBCIwIIIQd3d3LmxpbmtlZGluLmNvbYIM
bGlua2VkaW4uY29tMA4GA1UdDwEB/wQEAwIFoDAdBgNVHSUEFjAUBggrBgEFBQcD
AQYIKwYBBQUHAwIwawYDVR0fBGQwYjAvoC2gK4YpaHR0cDovL2NybDMuZGlnaWNl
cnQuY29tL3NzY2Etc2hhMi1nMy5jcmwwL6AtoCuGKWh0dHA6Ly9jcmw0LmRpZ2lj
ZXJ0LmNvbS9zc2NhLXNoYTItZzMuY3JsMEIGA1UdIAQ7MDkwNwYJYIZIAYb9bAEB
MCowKAYIKwYBBQUHAgEWHGh0dHBzOi8vd3d3LmRpZ2ljZXJ0LmNvbS9DUFMwfAYI
KwYBBQUHAQEEcDBuMCQGCCsGAQUFBzABhhhodHRwOi8vb2NzcC5kaWdpY2VydC5j
b20wRgYIKwYBBQUHMAKGOmh0dHA6Ly9jYWNlcnRzLmRpZ2ljZXJ0LmNvbS9EaWdp
Q2VydFNIQTJTZWN1cmVTZXJ2ZXJDQS5jcnQwDAYDVR0TAQH/BAIwADANBgkqhkiG
9w0BAQsFAAOCAQEAwaqukz1VifDjF2iVr6QzT4XX6hS0A6ZZO9u9SJH3/EDGsV5j
0H3Z7X62zHoXd4g4J8QUvfZ1etXFg685JFDyq1XHdpMl5uLc37H+3SXFEqsWSVUN
16HZQ49IiyHXDssxf9rKBpXRrSxAclfIrP9reC6BMAMxnF0cNrSuWgUIHCLxi3kQ
sUfjeJaRUWV1JdOVEJxTcrfM0HxycjoC5J+MQ5rlrWx+GPgeMGyQIGM4v2xGEXXp
XQEunwG92tLfMY0Dd4SUD0XIRlidQbREWz73NxqLyFap9lghcGdZMiVQSaGp7c8Y
vqQpESlJ2IQLnTMfbxN30WZnh4F2AGjltIT0cQ==
-----END CERTIFICATE-----
---
Server certificate
subject=/C=US/ST=California/L=Mountain View/O=LinkedIn Corporation/CN=www.linkedin.com
issuer=/C=US/O=DigiCert Inc/CN=DigiCert SHA2 Secure Server CA
---
No client certificate CA names sent
---
SSL handshake has read 1493 bytes and written 456 bytes
---
New, TLSv1/SSLv3, Cipher is AES128-SHA
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
Protocol : TLSv1
Cipher : AES128-SHA
Session-ID: 3158782D9374A7757632BCB6ED7980C3E7B36ABFD31B7448919C91B60151CC0A
Session-ID-ctx:
Master-Key: E3D2C374D16040B51BE6490F4DAFABC329DA94914165B6515F02F8E65DCE9683E62BFAC274942DFA0BABA5E2B3E32A3E
Key-Arg : None
Start Time: 1428692560
Timeout : 300 (sec)
Verify return code: 21 (unable to verify the first certificate)