The Authorisation header is missing

I keep getting this error when I check our site health tools:

The Authorisation header is missing

Flush permalinks

I have tried to flush the permalinks multiple times and I’ve also tried to add the below snippet of code on the C-panel:

RewriteRule .* – [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]

so the code looks like this:

# BEGIN WordPress
# The directives (lines) between "BEGIN WordPress" and "END WordPress" are
# dynamically generated, and should only be modified via WordPress filters.
# Any changes to the directives between these markers will be overwritten.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

but it did not work either.

do you have any other suggestions that I could try in order to fix this issue? Currently, some third party plugins cannot be connected to the site due to this issue.

Any feedback would be greatly appreciated.