HTTP ERROR 500 org.springframework.security.web.firewall.RequestRejectedException: The request was rejected because the URL contained a potentially malicious String "%25"

URI:/kommisjonen/medlemmer_%25C3%25A5s
STATUS:500
MESSAGE:org.springframework.security.web.firewall.RequestRejectedException: The request was rejected because the URL contained a potentially malicious String "%25"
SERVLET:dispatcherServlet
CAUSED BY:org.springframework.security.web.firewall.RequestRejectedException: The request was rejected because the URL contained a potentially malicious String "%25"