Installing private package from Github Package registry fails with not found/not authorized

Question

I created and published a private Github package. Trying to install it with yarn at first, I face the following issue:

Whether I try with yarn or npm, it cannot find

Answer 1

I am adding an answer here because after a day of trying different variations of the solutions here and elsewhere, I found that my issue was something else.

My issue was that, while npm is not case sensitive with regards to package names, yarn is when it comes to authentication!