Sometimes users complaint that when accessing jenkins an error happens 404 not found.
This is the error from tomcat localhost access logs:
172.25.1.123 - - [07/Aug/2019:10:21:16 +0100] "POST /j_acegi_security_check HTTP/1.1" 302 -
172.25.1.123 - - [07/Aug/2019:10:21:16 +0100] "GET /;jsessionid=8BD2593C17E0A692DCCE0EE1BF10A239 HTTP/1.1" 404 1047
This happened when upgraded to Jenkins ver. 2.187.
Users also say that after cleaning cache the problem stops but the next day trying to login again and the problem starts again.