Random 404 when Google Tag Manager is used

I want to set up Google Tag Manager for my WordPress website but I get random error 404 on my resources located in my upload folder (see below and screenshots)

I don’t use any plugin for Google Tag Manager. I edited my header.php file and pasted the 2 pieces of code as instructed.

Error 404 are random, sometimes the page loads fine sometime it doesn’t.

• I have a container who is published
• I did try to use the Google Tag Manager for WordPress plugin but with the same result.
• I did try to use an empty container but no success.

The issue seems to be with the 2 pieces of javascript we need to add in order to use GTM.

Any help of idea how to solve this issue.

Below are an exemple of errors I got:

[Error] Failed to load resource: the server responded with a status of 404 () (GDPR-pana-e1599900009880.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Search-engines-bro.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Website-setup-pana-e1599900002656.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Active-Support-amico.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Cloud-hosting-amico.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Pic-Intro-Service-social-media-1.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Devices-pana.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (post-609.css, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Devices-pana.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Pic-Intro-Service-social-media-1.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Active-Support-amico.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Cloud-hosting-amico.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Website-setup-pana-e1599900002656.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (GDPR-pana-e1599900009880.png, line 0)
[Error] Failed to load resource: the server responded with a status of 404 () (Search-engines-bro.png, line 0)