I also have the same issue, I'm using ubuntu 24.04 I perfectly installed tomcat 9 and it showed the welcome page, the problem began when I wanted to access manager-gui, I followed all the changes to be done on the cong/tomcat-user.xml file step by step one after the other. so the problem is when I enter the signing-in details, it flashes and gives the same signing-in prompt 3 times then it shows error 404, I do need you help.