If you want to use another brand of Ads other than AdSense, notice that you need to access the header section of AMP and add the code of your Ad provider.

lol. Did you hear about AdSense AUTO ads?
They generate the code you must put once in head and body and after that they will generate needed placement automatically…. as google says….

I know of this, and I set this up. But I want to set up AMP AUTO ADS which require 1 code to be set in the header and 1 in the body of the amp posts. How do I do this?

I have edited amp template and put needed codes to head and body section.
But If the plugins updates I will have to make it again =(

Open settings – permalinks, click on the type you already have selected and click save.
Helped for me with the same issue.

Have the same question regarding amp and category pages. How to enable amp for tags or category?

Of course I have used only that text

<IfModule mod_substitute.c>
SubstituteMaxLineLength 10M
</IfModule>

I work as linux admin.

Set up the below code in .htaccess!
<IfModule mod_substitute.c>
SubstituteMaxLineLength 10M
</IfModule>

That string makes 500 error.

We websitehas no errors in system status. All is set correctly.

What should I look for?
I do not have any additional plugins installed in wordpress. The installation is clean.

.htaccess contain only that

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress