Configuration update request failed

unknown

ZD1100  9.10.2.0 build 73
ZF7372 & R500
My many APs often disconnect from ZD but the wired network is not broken.

AP log :
ruckus syslog: eventd_to_syslog():AP[58:b6:33:32:8d:80] Configuration update request failed.  
ruckus syslog: eventd_to_syslog():AP[58:b6:33:32:8d:80] reset because its configuration is out of sync with ZoneDirector

I found that there are many received pause frames at HP 1920S 

How should I solve this problem?

Thanks!

unknown

make sure your APs can reach the ZD via port 21, FTP.