TL;DR
This isn't a solution, rather just what we tried (none of which worked).
This way, anyone else who might stumble on this question later might be able to offer other ideas/solutions.
As this other SO question/answer points out (which I didn't see until yesterday afternoon), it might be best to use another tool for Git and not rely on VS 2013's Git support.
Full explanation
From what I could find on the Net, the rather unhelpful error message is most likely indicative of certificate issues when trying to connect to / work with an https repository (as written about in this blog article):
Special considerations for HTTPS endpoints
If an HTTPS URI is used for a remote, the Windows certificate store is used to validate the server’s SSL certificate.
If the server to which you are pushing/pulling has a self-signed
certificate, then as of this writing, we give an unfortunate and vague
error message to the user. “An error occurred while sending the
request” [emphasis added by me] is what is commonly seen. You should use the Windows
certificate manager (certmgr.msc) to add the self-signed certificate
(or the authority at the top of the certificate’s chain) to the
Windows certificate store as a trusted certificate, and then try your
network operation again.
From the SO question (linked at beginning of answer) points out (which coincidentally links to the same article as above), it's not clear at all what certificate(s) would need to be added.
After more searching, I found another article that seemed might be related (dealing with SSL and certificate issues) (although it was regarding VS 2015, not 2013, and the error message wasn't the same):
Google pointed me at the .gitconfig file that lives at the root of
your user directory. When I looked at that it contained not much at
all – just a reference to the recently cloned repository I had tested
with above. So I added the setting necessary to tell Git to find it’s
trusted certificates in the same place that the command line tools had
reported:
[http]
sslcainfo = C:/Program Files/Git/mingw64/ssl/certs/ca-bundle.crt
And remarkably that fixed Visual Studio…
This is what I had Avi try:
- Close Visual Studio if open
- From a command prompt, run the following: git config --list
- From the output, see if there is a 'http.sslcainfo' entry.
It should/might have something like "C:\Program Files\Git...\certs\cabundle.crt"
- Copy that path
- In the gitconfig file in your user directory, try adding (replacing the path I show here with whatever the path from Step 4 is):
[http]
sslcainfo = C:/Program Files/Git/mingw64/ssl/certs/ca-bundle.crt
- Save the file
- Restart Visual Studio and try to connect/push/pull to the Github repo
Avi also tried importing the 'ca-bundle.crt' certificate into Windows Certificate Manager.
And last, but not least, Avi tried adding that same [http] block to the 'config' file under the specific repo's '.git' folder.