Invalid SSL certificate when pushing to Git server

Question 1

Git for Windows has its own trust store of trusted certificates which is normally located in the file

Git for Windows <=1.9: [Git installdir]\bin\curl-ca-bundle.crt (e.g., C:\Program Files (x86)\Git\bin\curl-ca-bundle.crt; configured by the key http.sslCAinfo in [Git installdir]\etc\gitconfig).
Git for Windows >= 2.0: [Git installdir]\mingwXX\ssl\certs\ca-bundle.crt where XX stands for 32 or 64 (e.g., C:\Program Files\Git\mingw64\ssl\certs\ca-bundle.crt; configured by the key http.sslCAinfo in git config, e.g. C:\Program Files\Git\etc or your global/local config).

Disabling checking of certificates (e.g., by setting git config http.sslVerify false) is not a good idea and might be extremely dangerous (as all security checks are disabled and MitM attacks are easily possible - depending where this is set it applies for all new https connections).

In order to add a certificate (may it be a self-signed one or another root certificate) to this trust store in order to automatically trust it, you have to perform the following steps (the first five steps are just to gather the certificate, this can also be done with your favorite browser, but might require different tasks):

Open the URL of the site in Microsoft Edge
Click on the lock symbol in the local bar and choose "Connection is safe" and then click on the certificate symbol.
(Optional) Select the certificate you want to trust on the certificate chain (third tab) and open it
Go to the second tab "Details"
Click on "Save to file", choose "Base64-encoded X.509 (.CER)" and save it with a unique name (remember that name; a name w/o spaces is recommended).
Now you have several options
1. Use a separate certificate trust store which only contains your just downloaded cert, by executing git config --global http.sslCAinfo "[yourfilename]" in a cli shell in order to only use this certificate as the trust store.
2. Use a separate certificate trust store which contains your just downloaded cert and all certificates from the git trust store, by appending all content from the system trust store file (path see above) and then execute git config --global http.sslCAinfo "[yourfilename]" in a cli shell in order to use this new trust store.
3. Update the system certificate file, by appending the content of your just saved file to [path-to-git-trust-store-crt-file] (e.g. by type [yourfilename] >> [path-to-git-trust-store-crt-file] in a cli shell running with administrative rights) OR using notepad (make a copy of the ca-bundle.crt file on desktop, append the content of the downlaoded .crt file and then copy it back). Disadvantage: changes might get overwritten on git update

Done. Now, this certificate is in the trust store of Git for Windows.

Recent versions of Git for Windows can use also Windows certificate store which might be more convenient in a corporate environment. This can be configured on installation.

Question 2

TortoiseGit is probably not using the same truststore Chrome. I think Chrome uses the system store, Firefox uses it's own. I have no idea what TortoiseGit uses.

On the client, if you set git config http.sslVerify false you may have more luck. You can also set this globally.

Question 3

Here is what worked for me. Create a folder C:\GitCerts. Then download the Base64 .cer file (follow the answer provided by MrTux) to this C:\GitCerts folder.

From command line run the following command: git config --global http.sslCAinfo "C:\GitCerts\MyCert.cer"
Open the MyCert.cer file in Notepad and leave it open
Open the Git ca-bundle.crt file in another Notepad. Mine was in the location C:\Program Files\Git\mingw64\ssl\certs\ca-bundle.crt.
Verify the cert text in the MyCert.cer file is in the ca-bundle.crt file (it should be), if not just copy and paste all the text from MyCert.cer and append it at the bottom of the ca-bundle.crt file (make sure you leave all the other cert information in there).

-----BEGIN CERTIFICATE-----

your cert info here

-----END CERTIFICATE-----

If you had to modify the ca-bundle.crt file then save it (you may have to save it to your Desktop and then copy and paste it back in to overwrite the ca-bundle.crt file)
Finally, based on the path of your ca-bundle.crt file run the following command: git config --global http.sslcainfo "C:\Program Files\Git\mingw64\ssl\certs\ca-bundle.crt"

Question 4

I experienced this error using GitHub and it seemingly came out of nowhere. I had done plenty of work on GitHub before.

Kaspersky anti-virus was the culprit!!

When I turned off my anti-virus protection (and waited a couple of minutes) I was able to push / pull from my github repo.

My final solution was to locate a certificate from Kaspersky then add it to the Git for Windows trust store. The latter step is already detailed in the accepted answer, but for anyone else in a similar position I was able to locate the Kaspersky certificate by going to:

Settings > Additional > Network > Encrypted connections scanning - Advanced Settings > Install Certificate > Show Certificate > Details > Copy to File > Base-64 encoded X.509 (.cer)

Question 5

For those in a corporates, who get the self signed certificate error - below is an alternative.

In corporates, the same git server, that is accessible over https protocol, usually will also be accessible over ssh protocol. So choose the ssh option of server url and clone the repository as

git clone user@server/project.git

Of course, the public key( id_rsa.pub ) from your ~\.ssh folder will have to added to server. This way you don't have add the https server certificate to your windows certificate store or mac keychain ( example ).

Question 6

I found one more answer for this issue :

$ git config http.sslVerify false

Question 7

I had the same problem because my laptop died and the clock reset to its default settings. If that's the case for you, set your clock to the current date and time and the problem should be fixed.

If your clock is set properly, follow what other people are recommending.

Question 8

I've had a similar problem, the error was "certificate has expired". After realizing that git uses own CA store I just updated Git and problem gone. P.S. BTW, recent Git for Windows can use Windows certificate store which can be more convenient in a corporate environment.

Question 9

If it's working previously and suddenly it stopped working with an SSL error then try to restart your system once. This way it worked for me

Question 10

I got the same error as I'm connecting through an insecure network. Switching the network resolved my issue.