Issue Email account looses the emails

[falcongr]

Hello
I am facing a strange situtation. I have setup a domain with 20 email accounts and the last two days one account suddenly lost all the emails from the inbox folder.If you check the size of the email account it gives you the correct amount but no messages in the inbox folder.The owner of this account keep control of his emails through roundcube webmail, he hasn't setup any email client (outlook,thunderbird etc.)
Up to now he was working ok .
I restore his email account from the backup and after a few minutes the inbox folder becomes empty again.
Your help will be much appreciated

 

[Bitpalast]

I suggest to check /var/log/maillog to find out who is logging in to the account at the time when the mails vanish.

 

[falcongr]

I checked and the owner of the mailbox is logging when the messages dissapears
I have run the plesk repair mail command also but with no luck
I attach a part of the logs maybe you can tell me more

Feb 7 21:43:56 server dovecot: service=imap, user=dp....@kb.....gr,
ip=[::1]. Error: Raw backtrace:
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(+0x9438e) [0x7f6a94b8c38e]
-> /usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(+0x9447c)
[0x7f6a94b8c47c] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(i_fatal+0) [0x7f6a94b25a4e]
-> /usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mail_index_sync_keywords+0x818)
[0x7f6a94ea3ed8] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mail_index_sync_record+0xf7)
[0x7f6a94ea48c7] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mail_index_sync_map+0x240)
[0x7f6a94ea58a0] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mail_index_map+0x21c)
[0x7f6a94e9c91c] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(+0x9cc6d)
[0x7f6a94eb2c6d] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(+0x9d273)
[0x7f6a94eb3273] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mail_index_open+0x78)
[0x7f6a94eb3368] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(index_storage_mailbox_open+0xf4)
[0x7f6a94e8bac4] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(+0x4b569)
[0x7f6a94e61569] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(+0x4b648)
[0x7f6a94e61648] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(+0x360a6)
[0x7f6a94e4c0a6] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mailbox_open+0x20)
[0x7f6a94e4c220] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(index_storage_get_status+0x20)
[0x7f6a94e8ad10] -> /usr/lib/dovecot/modules/lib10_quota_plugin.so(+0xcb0d)
[0x7f6a94341b0d] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot-storage.so.0(mailbox_get_status+0x37)
[0x7f6a94e4c607] -> dovecot/imap(imap_status_get+0x77) [0x4216e7] ->
dovecot/imap(cmd_status+0x188) [0x414c78] -> dovecot/imap(command_exec+0xa5)
[0x41a195] -> dovecot/imap() [0x4185e2] -> dovecot/imap() [0x418670] ->
dovecot/imap(client_handle_input+0x175) [0x418a05] ->
dovecot/imap(client_input+0x82) [0x418ec2] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(io_loop_call_io+0x4c)
[0x7f6a94ba0bdc] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(io_loop_handler_run_internal+0x10a)
[0x7f6a94ba209a] ->
/usr/lib/x86_64-linux-gnu/dovecot/libdovecot.so.0(io_loop_handler_run+0x25)
[0x7f6a94ba0c65]

 

[Bitpalast]

I checked and the owner of the mailbox is logging when the messages dissapears

What is your conclusion from that fact?

 

[falcongr]

not qualified to provide a conclusion

 

[Bitpalast]

Maybe we can find out together by summing up the facts:

First There are mails in the mailbox.
Then the owner logs in.
After the owner was logged in all mails are gone.

Who has done something? The server or the owner?

 

[falcongr]

The owner the only thing he did was to login as he did up to now so something is wrong at the server?

 

[Bitpalast]

"Oh, I forgot about my wife's computer."
"Oh, I forgot about the computer in the office upstairs."
"Oh, I forgot about the other smartphone I have."
"Oh, I forgot that my daughter is using the same box, too."
"Oh, is Outlook a mail client? I didn't know that this logging in, too."
"Oh, I thought you only meant IMAP, yes, sure I am using POP3 for downloading mails."
... endless possibilities.

 

[falcongr]

No it's more simple than you think, only one person has access to this email account, the account is up to now(2 years ) accessible through roundcube webmail and there is no account setup to any computer as POP3 or IMAP to any email client.