Same here, I get the 403 error in the launcher log for three tries before it gives up, shows the launcher login window and makes me login.
This is successful and I can start Minecraft just fine. however, the launcher keeps running at 100%CPU ( one mad thread I guess). But that might be another thing.
Native Launcher Version: 598
Operating System: OSX Version 10.14.6 (Build 18G103)
Still an issue in 1.13.2
Disable discord overlay and delete your versions folder
Still a thing in 1.14.4 - I need multiple restarts of the whole environment (lauchner etc) to get it working with just one click. Eventually (1-5 restarts) it works. Issue occurs with or without Optifine installed
iMac (late 2013 27") on Mojave 10.14.6 (18G1012)