Slack

Error message	Likely meaning (TL;DR)	Recommended next steps
Failed to open TCP connection to www.slack.com:443 (execution expired)	The request to www.slack.com:443 timed out, so the server couldn’t complete an outbound HTTPS connection (network/DNS/proxy/firewall issue).	Verify outbound connectivity from that host to www.slack.com:443 (allow it through firewall/proxy, ensure DNS resolves, and confirm your proxy settings if used).