Read User Mail - wont open mails from webmin Worked till Webmin 1.720

Kindly help me as I any webmin ver after 1.720 will show Read User Mail feature but will not open any email to read or reply.
I upgraded webmin 1.8* and on that server it wont work and says : Mail open user does not exist

On server with webmin 1.720 i can read the mails has following CONFIG and they are identical on webmin 1.872

I am using Mail server: Qmail+VPopMail.
The config of 1.720 is default which is :
Mail Server Installed:" qmail+VpoMail
User Mail file directory : Maildir
Mail file directory style : mail/username
Mail file in user home dir. Mailbox
Folders subdirectory under home dir. mail
Usermin Read Mail Config. dir. in home dir : usermin/mailbox

Base directory for VPOPMail : /home/vpopmail

I desperately need help to fix this issue as I do not see any resolution to this old issue. Kindly help me.
I will be most grateful. Thanking and look forward for your help.

I think Virtualmin/Webmin dropped support for Qmail somewhere past year. Not 100% sure so wait for official response, but this could be the reason why only works with old Webmin.

No, that’s not correct.

QMail is still supported. We dropped support for QMail-LDAP which is a different thing altogether; a fork of QMail that hasn’t been maintained in about a decade. We don’t recommend QMail, because it’s also pretty sporadically maintained and has no benefits over something like Postfix at this point, but we do still support it.

Sounds like a config problem. I’ve never used vpopmail, so I don’t know anything about how it’s laid out. But, it looks like your config is a little off.

You’ve got Maildir spools, right? So, the “mail/username” looks like an mbox configuration. You need a Maildir configuration if your mail is in Maildir spools (which, as far as I know, is what all QMail deployments would be).

Thanks Joe for help. I have on both servers with webmin 1.720 and latest exactly the same configurations.
On User mail file directory I have Maildir and mail file directory style is: mail/username , Folders subdirectory under home dir is : mail

It shows the users but wont open any mail.