Update: On Ubuntu 18.04 LTS, I got same error which is I got on Ubuntu 14.04 LTS. Now, I solved. In my case, it was firewall. Not on my system, it was on my institute’s policy. I contacted to IT guys and asked them to check the firewall during my installation and they found so many addresses (even qiime2.org) are blocked by their new firewalls (actually they said it is https something, I did not understand exactly but it was sort of firewalls). Anyway, IT guy released those address which cause the bad or failed handshaking and Now I installed Qiime2-2019.10 successfully both on Ubuntu 18.04 LTS and 14.04 LTS.
@yanxianl, if you are also in sort of institute, university or company, you can try contact IT guy on your workplace. maybe it will help.