Fresh Installed iRedMail on CentOS 7.3

Rebooted server and tried to access RoundCube portal. After login, showing the error message below:-

Server Error: STATUS: Internal error occurred. Refer to server log for more information. [2017-01-28 10:53:27] (0.000 + 0.000 secs).

==== Required information ====
- iRedMail version (check /etc/iredmail-release):
0.9.6
- Linux/BSD distribution name and version:
CentOS Linux release 7.3.1611 (Core)
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):
MariaDB
- Web server (Apache or Nginx):
Apache
- Manage mail accounts with iRedAdmin-Pro?
No
- Related log if you're reporting an issue:
Jan 28 10:50:26 mail dovecot: imap-login: Login: user=<postmaster@xxx.com>, method=PLAIN, rip=127.0.0.1, lip=127.0.0.1, mpid=27915, secured, session=<tNKiWSVHHtR/AAAB>
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/temp.mail.xxx.com.27915.86c3e0c38a1e450d) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: dovecot-acl-list creation failed: safe_mkstemp(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/temp.mail.xxx.com.27915.) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: unlink(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-acl-list) failed: Read-only file system (in acl-backend-vfile-acllist.c:335)
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open() failed with file /usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot.index.log: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist.lock) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: file_dotlock_create(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open() failed with file /usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot.index.log: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist.lock) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: file_dotlock_create(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open() failed with file /usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot.index.log: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist.lock) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: file_dotlock_create(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: open(/usr/project/mail/vmail1/xxx.com/p/o/s/postmaster//Maildir/dovecot-uidlist) failed: Read-only file system
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Drafts: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Drafts: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Drafts: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Sent: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Sent: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Sent: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Junk: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Junk: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Junk: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Trash: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Trash: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Trash: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Error: Failed to autocreate mailbox Trash: Permission denied
Jan 28 10:50:26 mail dovecot: imap(postmaster@xxx.com): Logged out in=559 out=2748
====