We checked your logs and found that PHP memory error probably is the reason of the problem with the header editor http://prntscr.com/wc4njm
You keep the 60 active plugins, it’s a lot, truly saying. So, if you want to use all these plugins then you need to increase the PHP memory limit.
Also, one of the plugins (Coupon Referral Program) generates the PHP notices https://prnt.sc/wbljgx Contact plugin to fix this because it creates a lot of logs.
