Content sub folder index.html error unmarshal failed: invalid character '{'

i have this content folder structure
Screen Shot 2024-03-24 at 22.10.11

i do not use any theme. i create a menu for each sub folder in content folder. when access to current menu, it successfully show the index.html inside current dir. but for blog menu, it says error unmarshal failed: invalid character '{'

this is my index.html in blog dir

{{range .Site.RegularPages}}
<td> <li><a href="{{.Permalink}}">{{.Title}}</a></li> </td>

basically i want to have a index.html page for menu blog to listing all md files
and i might have another folder that do the same thing as blog menu

Kindly need helps. Thank

Place content in content files.
Place template code in template files.

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