Cannot Login After Fresh Installation of v11

[trentmu]

Had a similar error a while ago, which got fixed with a pip version change, as in this post

[FYI/solved] yarn errors on bench update

I am still using v10.1.70/80 on a Debian Stretch 9.x manual install, and everything works perfectly I have seen in the past few weeks that there are many posts about yarn related errors during updates. I have/had not experienced any errors on my normal installation/server, but… While installing a backup/secondary machine to do some testing, I installed a v11 master copy (manually) and then downgraded to v10.x.x with a branch switch and did indeed, experience the yarn error. The…