If you accidentally delete or overwrite your “local” SharePoint certificate, you may find random things breaking such as Visio or Excel web parts, or things that require authentication.
You can check to see what certificate you have installed, and see if this might be the case by typing the following in Powershell:
Examine the “local” entry. If it does not say “SharePoint Root Authority” for the certificate, you will need to fix this. It should look something like this if it is correct:
If your cert does not look like the one above, and you have a multi-server farm, you should still be in luck. Log on to one of the other servers, and fire up SharePoint Management Shell.
Type the following:
$localCert = (Get-SPCertificateAuthority).RootCertificate$localCert.Export("Cert") | Set-Content "C:\localCert.cer" -Encoding byte
$localCert = New-Object System.Security.Cryptography.X509Certificates.X509Certificate2("c:\localCert.cer")
Set-SPTrustedRootAuthority -Identity "3e20f374-6d2e-4115-bbb8-40d9dd803d5d" -Certificate $localCert