I've set up a brand new site on 2.6.5.
As per my usual practice, I set up a head chunk. However I noticed it was not saving. On experimentation I see that it is not saving self-closing tags.
For example
<head>
<title>My test page</title>
</head>
Saves fine.
<head>
<base href="[[++site_url]]">
<title>My test page</title>
</head>
Will not save.
There are no errors. I have manually cleared the cache.
I have also tried:
<base href="[[++site_url]]" />
and I have tried using both a mark up plugin (Ace) and without.
Would anyone know what's going on here?
Usually it is because of mod_security. Kindly check with hosting support.
Another resource to consult, it is for MODX Revolution but server side situation would be similar and gives you clues: https://docs.modx.com/revolution/2.x/getting-started/installation/basic-installation/installation-on-a-server-running-modsecurity