Web 500 error with UserAjaxController

I don’t stop receiving this error : any idea ? :

Received From: raspberrypi->/var/log/apache2/access.log
Rule: 31122 fired (level 5) -> “Web server 500 error code (Internal Error).”
Src IP: (masked IP)
Portion of the log(s):

(masker IP) - - [24/Mar/2020:09:06:14 +0100] “GET
+/kanboard/?controller=UserAjaxController&action=status HTTP/1.1” 500 629 “-” “Mozilla/5.0 (Macintosh;
+Intel Mac OS X 10_10_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/80.0.3987.132 Safari/537.36”

–END OF NOTIFICATION