Ruckus R510 Frequent "Controller Connecting Error" Log

[kutlu_z_ng_r]

Hello Techs,
I have a WLAN installed with 3 R510 one acting as a master.There are around 180 clients connected to this network.All APs are connected to a firewall through a switch.Firewall is making DHCP.
There are issues regarding the connection of the clients to the APs.That is they drop frequently and it seems they can not establish connection again in some cases.(Not all the time)

Currently there are 30 clients on Master and around 70 on one slave and 80 on the other slave AP.

When I check the logs i see below error log in every 30 seconds;


Feb 21 09:06:14 Ruckus-Unleashed meshd[27258]: send_controller_config line: 96 Controller connecting error, errno: 2 No such file or directory 
Feb 21 09:06:14 Ruckus-Unleashed meshd[27254]: send_controller_config line: 96 Controller connecting error, errno: 2 No such file or directory 
Feb 21 09:06:13 Ruckus-Unleashed ZD-APMgr: IPC_thread rcv ping from TACMON 
Feb 21 09:06:11 Ruckus-Unleashed syslog: pid=1665, _loadXmlStr():Unable to parse XML string (null) 
Feb 21 09:06:11 Ruckus-Unleashed syslog: upgrade_debug: pid=27247, get_ap_list(): ap-list found !! 
Feb 21 09:05:47 Ruckus-Unleashed syslog: pid=1469, monitor():FileCache synced 
Feb 21 09:05:44 Ruckus-Unleashed meshd[27186]: send_controller_config line: 96 Controller connecting error, errno: 2 No such file or directory 
Feb 21 09:05:44 Ruckus-Unleashed meshd[27182]: send_controller_config line: 96 Controller connecting error, errno: 2 No such file or directory 
Feb 21 09:05:43 Ruckus-Unleashed ZD-APMgr: IPC_thread rcv ping from TACMON 


I wonder the meaning of this error and if it is anyhow related to failure of the reconnection of the clients to the APs.

Thanks in advance.