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

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

URI:	/Content/200923/cache=20190409164403/Avinor%2520AS%2520protokoll%2520fra%2520m%25F8te%2520i%2520valgstyret%252003092019%2520_signert.pdf
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"