php in iis

 threded php or non threaded php

load phpinfo

and then check 

Thread Safety  disabled

meaning thread safety is disabled and you need it for php extensions like

⚠ These extensions should NOT be in PHP 8.4:

Remove:

extension=php_json.dll

extension=json

extension=php_pcre.dll

extension=php_tokenizer.dll

extension=php_dom.dll

extension=php_xmlwriter.dll

extension=php_simplexml.dll

extension=php_xml.dll

Because in PHP 8+, these are built-in and do NOT have DLLs anymore.

👍 Correct Extensions Example for PHP 8.4

Your php.ini should have only extensions like:

extension=curl

extension=openssl

extension=mbstring

extension=mysqli

extension=pdo_mysql

extension=gd

extension=intl

extension=zip

extension=fileinfo

extension=exif

Everything else is built-in and must NOT be loaded manually

✅ Perfect — now we finally know the exact cause of your Google Sign-In internal error.

This has nothing to do with your PHP code.

The real issue is:

❌ cURL error 60: SSL certificate problem

Windows IIS + PHP cannot verify Google’s SSL certificate because the system does NOT have a CA bundle installed.

This is extremely common when moving PHP from Linux → Windows.

✅ FIX (Do this now)

Step 1 — Download latest CA bundle

Download this file:

👉 https://curl.se/ca/cacert.pem

Save it here:

C:\php\extras\ssl\cacert.pem

(If the folder doesn’t exist, create it.)

Step 2 — Edit php.ini

Find:

;curl.cainfo =

;openssl.cafile =

Change to:

curl.cainfo = "C:\php\extras\ssl\cacert.pem"

openssl.cafile = "C:\php\extras\ssl\cacert.pem"