I installed the Zabbix agent on a AIX machine. Though it works well, I have the following error repeated countless time. 

zabbix_agentd [8388944] Is this process already running? Could not lock PID file [/tmp/zabbix_agentd.pid]: [13] Permission denied

The Zabbix agent version is: 

$ /opt/zabbix/sbin/zabbix_agentd -V
zabbix_agentd (daemon) (Zabbix) 4.0.7
Revision 92831 18 April 2019, compilation time: May 10 2019 08:40:52

Copyright (C) 2019 Zabbix SIA
License GPLv2+: GNU GPL version 2 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it according to
the license. There is NO WARRANTY, to the extent permitted by law.

Supported technology levels: 6100 and above

The PidFile configuration variable is set to the default value:

1. PidFile=/tmp/zabbix_agentd.pid)

 A search on internet let me see other people with the same problem but without any solution.  

Does a solution exist for this problem?