CSS Disabled automatically in SharePoint online site

[Amit Koyani]

Scenario: I have created a custom master page for our site, all the custom JS and CSS is been on master page folder

Error: one of sudden day All the CSS are disabled automatically, I have checked with the network there are not any blockage from the firewall

Temporary Solution: Temporary solution I found that when I check out the page it works fine but after publish it ruins 

Looking for expert advice on that

Tried Solution: I tried to publishing feature ON/OFF but not works in my case

even Default master page (seattle and oslo ) have the same issue

[#2]

In SharePoint Online you should avoid the creation of master pages...if you create a master page for a SPO site and you apply it, you are going to disconnect that sites from many innovations being added by Microsoft...Migh I ask why are you creating a custom master page for SPO?

[#3]

@Juan Carlos González Martín Yea I have created a custom master page, even if I applied default master page oslo and seattle error remain same