I suspect the source of the problem is this line
HTTP request failed: Protocol “stratum+tcp” not supported or disabled in libcurl
libcurl is a library (developed for the command-line “curl” program that can be used to fetch web-pages).
I suspect the most likely way to fix your problem is by updating MacMiner to the latest version and by checking that your computer also has the latest version of the libcurl library (using whatever package manager is appropriate for your computer)
I’m not familar with MacMiner or slushpool but you may also be able to configure MacMiner to use HTTP instead of STRATUM+TCP?