6/28/19, 21:53:13.840 [NOTICE] Bootstrapped 5%: Connecting to directory server 6/28/19, 21:53:13.844 [NOTICE] Bootstrapped 10%: Finishing handshake with directory server 6/28/19, 21:53:15.260 [NOTICE] Bootstrapped 15%: Establishing an encrypted directory connection 6/28/19, 21:53:15.517 [NOTICE] Bootstrapped 20%: Asking for networkstatus consensus 6/28/19, 21:53:34.859 [WARN] Proxy Client: unable to connect to 188.8.131.52:443 ("general SOCKS server failure")
That log shows that Tor couldn't connect to one of the Proxy clients. If that's the last message that you got, then the issue is pretty minor. One of the many proxies are unavailable.
Simply try to connect again.
If you're behind a filtered network, try rotating bridges by clicking on the button that says "Configure Tor", and choosing a bridge from the list. Then try to connect.