Zend certified PHP/Magento developer

Magento 2.3.4 admin not saving

Good day,

From magento ce 2.3.4 admin just in configuration module I can not save or saving button is not working:

a) Firefox most of the time not working

B) google chrome sometimes not working

c) Microsoft edge works ok

console says:

“TypeError: d[0] is undefined” related to https://cdn.mysite/pub/static/versionxxxxxx/adminhtml/Magento/backend/en_US/Dotdigitalgroup_Email/js/node_modules/fancybox/jquery.fancybox.pack.min.js

In order to resolve the issue I have tried:

  • fix permissions of folder and files, no luck
  • clear and flush cache, sometimes works
  • deploy the site, sometimes works

anyone has a solution or experiences the same issue?

at the same time, I am using, nginx, varnish apache and pagespeed.