autocreate plugin is deprecated, use mailbox { auto } setting instead

Hi,

Testing a few email accounts in Roundcube

I can send out emails but can't receive any, testing with gmail account.

Looked at /var/log/dovecot.log

Feb 15 04:07:36 imap(me@domain.it): Warning: autocreate plugin is deprecated, use mailbox { auto } setting instead

/var/log/maillog

Feb 15 04:28:59 svr1 postfix/smtpd[18842]: warning: unknown[ip]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Feb 15 04:29:00 svr1 postfix/smtpd[19641]: warning: unknown[87.246.7.000]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Feb 15 04:29:00 svr1 postfix/smtpd[18315]: warning: unknown[ip]: SASL LOGIN authentication failed: UGFzc3dvcmQ6
Feb 15 04:29:00 svr1 postfix/smtpd[18315]: disconnect from unknown[ip] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Feb 15 04:29:00 svr1 postfix/smtpd[18809]: connect from unknown[ip]
Feb 15 04:29:00 svr1 postfix/smtpd[18842]: disconnect from unknown[ip] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Feb 15 04:29:00 svr1 postfix/smtpd[19641]: disconnect from unknown[87.246.7.000] ehlo=1 auth=0/1 rset=1 quit=1 commands=3/4
Feb 15 04:29:03 svr1 postfix/smtpd[15533]: warning: hostname net6-ip000.linkbg.com does not resolve to address 87.246.7.000: Name or service not known
Feb 15 04:29:03 svr1 postfix/smtpd[15533]: connect from unknown[87.246.7.000]
Feb 15 04:29:03 svr1 postfix/smtpd[19486]: connect from unknown[ip]
Feb 15 04:29:04 svr1 postfix/smtpd[18315]: connect from unknown[ip]
Feb 15 04:29:05 svr1 postfix/smtpd[18842]: connect from unknown[ip]

Any advice appreciated

This message keeps coming back to gmail

###################################################################
# THIS IS A WARNING ONLY.  YOU DO NOT NEED TO RESEND YOUR MESSAGE. #
####################################################################

Your message could not be delivered for more than 4 hour(s).
It will be retried until it is 5 day(s) old.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<billing@domain.com>: temporary failure. Command output: Can't open log file
    /var/log/dovecot.log: Permission denied

I'm not sure what to fix, I can't receive emails to any email address in Roundcube, but I can send them out.
I did delete and recreate the dovecot.log it's current permissions are set to 600, root user.

Any help appreciated.

Check the disk space available.

It's a new server with 2 500 gig drives