can't post to craigslist from Vietnam

I am in Vietnam right now. I can't post to the discussion forums no matter what I do -- trying different browsers, different operating systems (linux, android), operating through a vpn with a server in the U.S. to make my IP and DNS server appear domestic to CL. Nothing works.
I must have tried to post at least a dozen times using all the tricks I could think of, on various forums (xyz, travel, android).
I've tried to post using a couple of other old CL handles I have.
For days now, not a single character I type gets through to CL. What is the cause and how to solve this problem? If vietnam were blocking CL, my expressvpn would have got around the block; expressvpn worked without a hitch getting through the firewall when I was in China. So I can't figure out what's causing this problem. It's a real mystery.