Error while Installing Crashlytics (3.14.0) - cannot find zipfile directory

Backstory

We just updated the macOS to macOS Catalina and the problems came; it was working perfectly on on an older macOS. We had to manually trust the fabric.io cert for the download to go through:

> Downloading dependencies
> Installing Alamofire (4.9.1)
> Installing Crashlytics (3.14.0)
>
> [!] Error installing Crashlytics
> [!] /usr/bin/curl -f -L -o
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200102-10389-1do3j4/file.zip
> https://kit-downloads.fabric.io/cocoapods/crashlytics/3.14.0/crashlytics.zip
> --create-dirs --netrc-optional --retry 2
>
> % Total % Received % Xferd Average Speed Time Time Time
> Current
> Dload Upload Total Spent Left Speed
>
> 0 0 0 0 0 0 0 0 --:--:-- --:--:--
> --:--:-- 0 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0 curl: (60) SSL certificate problem: self signed certificate in certificate chain More details here:
> https://curl.haxx.se/docs/sslcerts.html
>
> curl failed to verify the legitimacy of the server and therefore could
> not establish a secure connection to it. To learn more about this
> situation and how to fix it, please visit the web page mentioned
> above.

Current problem

Once the cert issue was solved we got an installation error.

> Downloading dependencies
> Installing Alamofire (4.9.1)
> Installing Crashlytics (3.14.0)
>
> [!] Error installing Crashlytics
> [!] /usr/bin/unzip
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4/file.zip
> -d /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4
>
>
> Archive:
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4/file.zip
> End-of-central-directory signature not found. Either this file is not
> a zipfile, or it constitutes one disk of a multi-part archive. In the
> latter case the central directory and zipfile comment will be found on
> the last disk(s) of this archive.
>
> unzip: cannot find zipfile
> directory in one of
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4/file.zip
> or
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4/file.zip.zip,
> and cannot find
> /var/folders/l0/whv35ab91t90r2ksnt6v01872000gn/T/d20200106-92577-1do3j4/file.zip.ZIP,
> period.

The folder does not exists, so I am not sure if curl went wrong or they did a cleanup of the folder. Any idea why this is happening and how to solve it?

Turns out that our computer were using a self-signed certificate (and to make things even more complicated we were behind proxies), and certificate trust errors were appearing. Went to Safari and load the url, accessed the site, and it prompted me to approve the site. This stores the certificate into the Keychain Access. Went to the certificate in the Keychain Access in question, get its info and changed it to Always Trust. Problem solved.