Game launcher not working

Just tried launching the game and it is getting stuck at the Patch Notes check screen. Patch 3.19.1d Patch notes which I downloaded several days ago and have played with since updating. Today the launcher hangs on 0.00% and eventually returns an error pop-up:

Connection failure

Error: Received HTTP 504 while downloading
http://patchcdn.pathofexile.com/3.19.1.4/PathOfExile_KG.exe

Same error here

It just fixed itself - try again

Unfortunately, no such successful resolution for me. 10 hours later and it's still broken with no ability to launch and displays the same type of Connection failure error, although this time it appears to be trying to launch the 64 bit version of the game:

Error: Received HTTP 504 while downloading
http://patchcdn.pathofexile.com/3.19.1.4/PathOfExile_x64_KG.exe

I don't know if region has anything to do with it. I'm in Australia.

... and now it randomly connects.

Not sure if it might happen again though but for now, I'm in.

same problem but it fixed the problem by going to Control Panel\Programs\Programs and Features then select Path of Exile and click on Change (Not Unistall), when poe setup window show, click on repair. it fixes it but the bug will show again every now and then if it does just do the same process. I hope GGG will fix this problem.

Unfortunately we're back to the original problem of the game not launching. I tried the repair fix and although the system said the repair was successful, still no launch.

Same problem, launcher sits there doing nothing