Otherwise browser cache it and we cannot login.

As you can see in the Network tab :

First time I entered the webrunner, there was no account, so from / I was redirected to /setAccount.

Then after setting account, when I click login button, this possed to doLogin, then redirect to / but the browser (chrome does this, not firefox) has cached that "/ redirect to setAccount", so it redirects to setAccount, which in turn redirect to /login. Back to login form and I cannot login.

83e98540 was wrong, the redirect code when no account exists should not be

but

@alain.takoudjou please confirm this account creation page is still used after your recent changes, I left a comment on 3f9029ba

/cc @rafael

PS: please also have take look at the discussions on https://www.erp5.com/group_section/forum/Where-can-I-find-Password-Recovery-code-of-web-runner