Hello, I have the exact problem as mikee1001. The answer “You just need to manually select a different language code for the second language.” does not work since wordpress sent the 2 following messages :
The new local code is not valide
the laguage code shoud be unique
Therefore, it is not possible to have several local language codes for one same language code “en”.
What else can I do? (I am not a developper) Delete le language code “en_US” and start from scratch with a new “en_GB”?