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/124239/cache=20200106170010/Veileder%25201-%25201.9.14.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"