Defender locking out media uploads

Hi there,

Defender occasionally is locking out users who are uploading media files. Their IPs are showing as MAC IPs so it wont let me add them to the white list. This has happened on multiple occasions. Attached screenshots, I've also enabled support access.

  • Kasia Swiderska
    • Support nomad

    Hello Brandon,

    That strange – those are 404 errors – strange that they show while uploading images. Can you check with those users if they are had trouble with uploading those images before they were locked out?

    Also you should be able to exclude those users by disabling option "Monitor 404s from logged in users"

    let me know if this will help.

    kind regards,


  • Brandon
    • Design Lord, Child of Thor

    Hi Kasia Swiderska we just did some testing and it happened again, even though the 404 option for users was disabled. We think it might be something to do with uploading a png – Smush converts it to a jpg and presumably at some point in the process the png is no longer available so Defender sees it as a 404 error and locks you out.

  • Nithin
    • Support Wizard

    Hi Brandon,

    It just locked us out again actually, we did something different – we just tried to change the slug then got this…

    Was 404 detection option disabled while you were changing the slug? Are you noticing this issue in Author user role, or for Admin? Could you please point out a user account on which you noticed all these issues?

    From the screenshot it seems like it’s an issue only for admin account? I tried to replicate the same in your system, but I’m not able to notice the issue when 404 is enabled/disabled. I even tested in my system, but I wasn’t able to generate such any issue. Is there any steps that you have noticed to generated this error?

    Is it a live site? Is it possible for you to check whether you are able to notice the same by disabling all the plugins except Defender, and then see how that goes?

    I’m also checking this with the developer to have a better idea regarding this, will keep you posted. Please do advise if I’m missing something here, have a nice day. :slight_smile:

    Best Regards,


  • Brandon
    • Design Lord, Child of Thor

    – 404 was enabled but we disabled it because it was randomly blocking people and our client was freaking out.

    – The lockout would happen to admins and editors (those are the only two roles being used I think) and also users that are just looking at the site. I logged out and used the site for a while and it locked me out when I was trying look at an archive. When I looked at the logs it said I was trying to hit pages that weren't there (but I was only on one page) it might have something to do with the theme? Attached screenshot of those lockouts.

    – The media lockout seemed to happen when we uploaded .pngs, randomly

    – Yes it's a live site so we can't do too much testing

    Also, on a different site, I noticed that at some point defender had locked all usage and our caching system had cached the defender page. Even when we deleted defender from their site the defender lockout was still showing from the cache. Because of this we've disabled the 404 detection on all our sites.

  • Nithin
    • Support Wizard

    HI Brandon,

    Thank you for providing more information, this is really odd. I’m passing your observations to the developer, and will ask for his feedback regarding this.

    Please do note that developers work round the clock with many critical issues, and hence have a slow response time. Either myself, or the developer will keep you posted asap.

    Kind Regards,


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