A few days ago I created a new "system administrator" user in this way:
service setup - users - new
user license: salesforce
profile: system administrator
But now I can't. I don't have the option "salesforce" for the "user license" field that is the only license that allows the "system administrator" profile. Now "user license" has only these options:
[...] partner app subscription salesforce platform work.com only [...]
Why is "salesforce" option missing?