First reported on French Wikisource (in French) : https://fr.wikisource.org/wiki/Wikisource:Scriptorium/Septembre_2019#Mot_de_passe_incorrect%2C_ou_autre_chose
A user (User:Wuyouyuan) reported that he was not able to log in using his usual password and when he tried to reset his password, he received the error message "You cannot reset user's passwords because you are blocked globally." He does not seems to be blocked on any wiki.
Maybe not the user is blocked, but the IP used by the user. Global blocks can also prevent login.
The user can visit Special:MyContributions logged out to see if there is a global block shown at the being of the page
See https://fr.wikisource.org/wiki/Spécial:GlobalBlockList for an list of global blocks
As Umherirrender wrote, it was a IP problem. I use routinely a VPN (I am very often in China and I have the "IP exempt" privilege) and the VPN was on, it's IP blocked by the wiki. I was mystified by the answer to a request in the "lost password ?" procedure : "You are globally blocked", believing I, user, was blocked. Suggestion: replace the text "You are globally blocked" by "The IP you are using is globally blocked."
Change 569382 had a related patch set uploaded (by Urbanecm; owner: Urbanecm):
[mediawiki/extensions/GlobalBlocking@master] i18n: Rephrase globalblocking-blocked-nopassreset to make it clear IP address is blocked
Change 569382 merged by jenkins-bot:
[mediawiki/extensions/GlobalBlocking@master] i18n: Rephrase globalblocking-blocked-nopassreset to make it clear IP address is blocked