SSL_connect: SSL_ERROR_SYSCALL in connection to github.com:443

Question

Since a few days I got an issue with Mac OS High Sierra 10.13.3 : When I run a git clone like git clone github.com/xxx.git failed it print:

Answer 1

I have a similar issue and I just found that in my case it may be the antivirus that creates an issue.

At some moment I've got the same error while trying to pull some data from github.com.

I knew that Kaspersky is intercepting the SSL connections to check for malicious content from the sites and I decided to disable it, but I found that KAV is hung and not really responding, so I just closed Kaspersky and tried to connect to github.com again and alas! I was able to connect successfully to GitHub.

So in you case it may be a similar issue.