Fails with "Page Not Found" when Base URL is HTTPS

[SylvainGlobalia]

Bug Report

I am experiencing an issue where Craft Sherlock fails to connect to the site's own Base URL when running the check, resulting in a

Not Found: Unable to connect to ... Please ensure that the site is reachable and that the system is turned on.

I think it's the TestsService.php file, line "$response = $this->client->get($this->siteUrl);"
Maybe the failing call originates in Guzzle's request() method, as the plugin attempts to fetch content from the primary site URL.

Environment Details
Plugin: Craft Sherlock (Using commit 8e11c05 temporarily)
Craft CMS: 5.7.10 Pro
PHP: 8.2.28

Base URL: https://stage.jsheld.com/ (Confirmed via Settings -> Sites)

Steps to Reproduce
Navigate to the Sherlock utility page in the Craft Control Panel.

Execute the Sherlock checks.

Observed Behavior
The check that performs an internal Guzzle request to the site's own Base URL (e.g., to https://stage.jsheld.com/) fails with the following message:

Page Not Found
Unable to connect to "https://stage.jsheld.com/". Please ensure that the site is reachable and that the system is turned on.

Verification
We have verified that the server can successfully connect to the public URL using curl from the command line.

Plugin Version

5.2.0 Using commit 8e11c05 temporarily

Craft CMS Version

5.7.10

PHP Version

8.2.28

[bencroker]

When I run curl -I https://stage.jsheld.com/ I get a HTTP/2 403 response header, likely blocked by Cloudflare as the response body contains:

<title>Attention Required! | Cloudflare</title>

[SylvainGlobalia]

Hello,
It's been a while but we haven't solve this issue.
If we do curl -I https://stage.jsheld.com/ there is no more Cloudflare blocking, but we still see the error:

Any idea, thoughts ?

[bencroker]

Are you able to successfully run curl -I https://stage.jsheld.com/ from the staging server itself?