Zotero connecter suddenly stopped working

Zotero connecter was working fantastically in my Brave browser and Ubunut desktop app. But recently it complains that the desktop app is unavailable and refuses to add the papers.

this web page :
http://127.0.0.1:23119/connector/ping
states 'Zotero Connector Server is Available'

Can I get some help with this please?
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