In some cases, you may have to install an intermediate VeriSign certificate to extend the lifespan of an expired certificate:

The intermediate certificate can be easily installed by concatenating it to the original certificate in the cert.pem file. When you are copying the intermediate certificate from your certificate vendor and pasting it to your cert.pem file, make sure that you have removed any extra line feeds and hidden characters. Below is an example of the cert.pem file after the intermediate certificate is appended to the original certificate.

Note: This is a non-working certificate.

-----BEGIN CERTIFICATE-----
aVNpZ24gVHJ1c3QgTmV0d29yazEXMBUGA1UECxMOVmVyaVNpZ24sIElu
jQAwgYkCgYEA2IKA6NYZAn0fhRg5JaJlK+G/1AXTvOY2O6rwTGxbtueqPH
TElBQklMSVRZIExURC4oYyk5NyBWZXJpU2lnbjCBnzANBgkqhkiG9w0BA
jQAwgYkCgYEA2IKA6NYZAn0fhRg5JaJlK+G/1AXTvOY2O6rwTGxbtueqPH
veqXQu2aNAoV1Klc9UAl3dkHwTKydWzEyruj/lYncUOqY/UwPpMo5frxCTvzt
OfdcSVq4wR3Tsor+cDCVQsv+K1GLWjw6+SJPkLICp1OcTzTnqwSye28CAwE
-----END CERTIFICATE-----
-----BEGIN CERTIFICATE-----
MIIDgzCCAuygAwIBAgIQJUuKhThCzONY+MXdriJupDANBgkqhkiG9w0BA
MQswCQYDVQQGEwJVUzEXMBUGA1UEChMOVmVyaVNpZ24sIEluYy4x
LkNsYXNzIDMgUHVibGljIFByaW1hcnkgQ2VydGlmaWNhdGlvbiBBdXRob3J
HhcNOTcwNDE3MDAwMDAwWhcNMTExMDI0MjM1OTU5WjCBujEfMB0
aVNpZ24gVHJ1c3QgTmV0d29yazEXMBUGA1UECxMOVmVyaVNpZ24sIElu
TElBQklMSVRZIExURC4oYyk5NyBWZXJpU2lnbjCBnzANBgkqhkiG9w0BA
jQAwgYkCgYEA2IKA6NYZAn0fhRg5JaJlK+G/1AXTvOY2O6rwTGxbtueqPH
veqXQu2aNAoV1Klc9UAl3dkHwTKydWzEyruj/lYncUOqY/UwPpMo5frxCTvzt
OfdcSVq4wR3Tsor+cDCVQsv+K1GLWjw6+SJPkLICp1OcTzTnqwSye28CAwE
4zCB4DAPBgNVHRMECDAGAQH/AgEAMEQGA1UdIAQ9MDswOQYLYIZI
KjAoBggrBgEFBQcCARYcaHR0cHM6Ly93d3cudmVyaXNpZ24uY29tL0NQUz
HSUELTArBggrBgEFBQcDAQYIKwYBBQUHAwIGCWCGSAGG+EIEAQYK
ATALBgNVHQ8EBAMCAQYwEQYJYIZIAYb4QgEBBAQDAgEGMDEGA1
oCKGIGh0dHA6Ly9jcmwudmVyaXNpZ24uY29tL3BjYTMuY3JsMA0GCSqGS
1RPuKSvD5HKNRO3RrCAJLeH24RkFOLA9D59/+J4C3IYChmFOJl9en5IeDC
-----END CERTIFICATE-----

A copy of the new Intermediate Root CA is available at the following link:

https://www.verisign.com/support/site/caReplacement.html