Problem opening Usermin Inbox


My client just install Centos7 and provided me with server access. I installed webmin and virtualmin then configure it to use for a domain...

Now problem is when I check usermin of main domain email id it showing the error

An error occurred listing mail in this folder : Failed to login to POP3 server : Internal error occurred. Refer to server log for more information

[root@mail lib]# netstat -lnp |grep :110 tcp 0 0* LISTEN 20630/dovecot tcp6 0 0 :::110 :::* LISTEN 20630/dovecot

I check online my open ports and it is showing PORT STATE SERVICE

20/tcp closed ftp-data 21/tcp closed ftp 22/tcp open ssh 25/tcp open smtp 53/tcp open domain 80/tcp open http 110/tcp open pop3 143/tcp open imap 443/tcp open https 587/tcp open submission 993/tcp open imaps 995/tcp open pop3s

I tried adding mail location (currently it is not in /etc/dovecot/dovecot.conf but still failed to remove that error

I check logs and got this error:

dovecot: pop3-login: Disconnected (no auth attempts in 0 secs): user=<>, rip=, lip=, secured, session=<EB/U5qdFfgDZDHse> Jan 9 13:45:18 mail dovecot: pop3-login: Login: user=<bounce.topkuv>, method=PLAIN, rip=, lip=, mpid=13929, TLS, session= Jan 9 13:45:18 mail dovecot: pop3: Error: user bounce.topkuv: Mail access for users with UID 501 not permitted (see first_valid_uid in config file, uid from userdb lookup). Jan 9 13:45:18 mail dovecot: pop3: Error: Invalid user settings. Refer to server log for more information.

Kindly help me on this.. If required access, I can provide it.

Thanks Kishan Giri


Howdy -- you may want to look in the Dovecot configs for a "first_valid_uid" parameter... I suspect it's set to something like "1000".

Try setting that to 500, and then restart Dovecot.

Out of curiosity, was this a dedicated server where you performed the Linux installation? Or was the installation part of a VPS image, or otherwise done by your provider?

I have a server that is using your latest cloudmin 9.1.kvm GPL and I encountered the same exact problem using the kvm-64-centos7.0-base (CentOS 7.0 64-bit KVM instance with base OS)

I changed the setting in "User and Login Options" - "Minimum valid UID" from 1000 to 500

Applied Configuration and all is working fine now.

Thank you,

Note that future releases of Webmin will increase the initial UID for allocation to new users from 500 to 1000.

tpnsolutions's picture
Submitted by tpnsolutions on Sun, 03/19/2017 - 00:15 Pro Licensee


FYI: I just had to address the UID issue with a client who installed Virtualmin only a few weeks ago. Virtualmin is still issue UID's lower than 1000, which caused Dovecot to complain.

OS: CentOS 7


You can increase the min for new uses right now by editing /etc/webmin/useradmin/config

tpnsolutions's picture
Submitted by tpnsolutions on Mon, 03/20/2017 - 03:46 Pro Licensee


I successfully addressed the matter using a solution recommended by Eric earlier. But just wanted to mention that "by default" the "min" setting is still "500" which causes an issue with the default "min" value in Dovecot on CentOS 7 (at least).

Hence, I was merely pointing this out so that the default within Virtualmin gets addressed in future releases, as it could be seen as a bug to users who don't have this knowledge.


Yes, the next Webmin release will increase the default min UID to 1000 (on CentOS)