I found an issue: MCL-5511 which looks exactly what I have.

I cannot play at all. Please help.

This is my launcher terminal text:

Last login: Wed Aug 28 16:38:24 on console

/Applications/Minecraft.app/Contents/MacOS/launcher ; exit;

Josephines-iMac:~ Aoife$ /Applications/Minecraft.app/Contents/MacOS/launcher ; exit;

2019-08-28 16:51:22.437 launcher[1344:175741] Claimed it found a path: /Applications/Minecraft.app/Contents/MacOS/launcher (/Applications/Minecraft.app/Contents/MacOS/launcher) 4096

https://launchermeta.mojang.com/v1/products/launcher/022631aeac4a9addbce8e0503dce662152dc198d/mac-os.json

GVA info: Successfully connected to the Intel plugin, offline Gen95

[0828/165123.168759:ERROR:node_channel.cc(902)] Error on sending mach ports. Remote process is likely gone. Dropping message.