kopano-dagent disk error (80040116)

I have freshly installed kopano 8.5.4.0 on CentOS 6 and created two users.
It is not possible to send an email from one user to another:

Wed Mar  7 18:41:25 2018: [14503] [error  ] virtual HRESULT M4LMsgServiceAdmin::ConfigureMsgService(const MAPIUID*, ULONG_PTR, ULONG, ULONG, const SPropValue*): MSGServiceEntry failed: logon failed (80040111)
Wed Mar  7 18:41:25 2018: [14503] [crit   ] CreateProfileTemp(): ConfigureMsgService failed 80040111: logon failed
Wed Mar  7 18:41:25 2018: [14503] [warning] CreateProfileTemp failed: 80040111: logon failed
Wed Mar  7 18:41:26 2018: [14503] [error  ] Unable to commit message: disk error (80040116)
Wed Mar  7 18:41:26 2018: [14503] [error  ] Unable to deliver message to "yythoss", error code: 0x80040116
Wed Mar  7 18:41:26 2018: [14503] [error  ] HRESULT ProcessDeliveryToSingleRecipient(pym_plugin_intf*, IMAPISession*, LPADRBOOK, FILE*, recipients_t&, DeliveryArgs*): ProcessDeliveryToServer failed: disk error (80040116)
Wed Mar  7 18:41:26 2018: [14503] [error  ] int main(int, char**): deliver_recipient failed: disk error (80040116)
Wed Mar  7 18:42:01 2018: [error  ] WARNING: setrlimit(RLIMIT_NOFILE, 8192) failed, you will only be able to connect up to 1024 sockets. Either start the process as root, or increase user limits for open file descriptors (Operation not permitted)

“disk error” usually means the server is not able to properly write to the database.

the problem was the rights on the attachment_path
after this, everything works fine:

chmod 755 /path/to/attachment -R
chown kpano:kopano /path/to/attachment -R