Fix PHP Website Forms PHPMailer, Google SMTP and reCAPTCHA v2

Fix Two PHP Website Forms Using PHPMailer, Google Workspace SMTP and reCAPTCHA v2

I need an experienced PHP developer to diagnose and fix two forms on an existing live website:

1. Contact Us form
2. Book a Free Design Visit form

Website: https://www.cleverstoragekent.co.uk

Both forms previously worked on the same eUKhost VPS using PHPMailer, Google Workspace SMTP and Google reCAPTCHA v2. The website files were recently replaced with an updated version, and both forms now reach the branded error page when submitted.

Current setup:

- PHP 8.2 with PHP-FPM
- PHPMailer included locally in the website files
- Google Workspace SMTP
- SMTP server: `smtp.gmail.com`
- Port: `587`
- Encryption: TLS/STARTTLS
- Google reCAPTCHA v2 checkbox
- Website hosted on an eUKhost VPS
- Contact Us handler: `general-contact.php`
- Design Visit handler: `contact.php`
- Shared settings: `config.php`
- Shared email code: `form-common.php`
- Optional photograph uploads on the Design Visit form

eUKhost has confirmed:

- Outbound connections to `smtp.gmail.com` on port 587 are permitted
- The server can resolve and connect to Google SMTP
- TLS negotiation and certificate verification succeed
- PHP OpenSSL is working
- No firewall or ModSecurity restriction is blocking SMTP
- The upload directory is writable
- Required PHP extensions are installed

Required work:

- Diagnose the precise PHPMailer or Google SMTP failure.
- Restore successful delivery for both forms.
- Confirm that each form redirects to the thank-you page after successful submission.
- Confirm that failed submissions redirect to the correct error page.
- Verify reCAPTCHA v2 on both forms.
- Check that the authenticated sender matches the Google Workspace account.
- Check PHPMailer’s SMTP, encryption and authentication settings.
- Ensure confidential credentials remain protected.
- Test the Contact Us form from the production domain.
- Test the Book a Free Design Visit form from the production domain.
- Confirm staff notification emails are received.
- Confirm customer acknowledgement emails are received where configured.
- Test optional photograph uploads from iPhone/Apple Photos.
- Ensure valid JPEG, JPG, PNG, WebP, HEIC and HEIF photographs are handled safely.
- Prevent PHP execution inside the uploads directory.
- Remove any temporary debugging files or detailed public error messages when finished.

Please do not redesign the website or change unrelated pages. This is a focused server-side form repair.

Access can be provided to the relevant eUKhost files and logs. The successful developer should explain the cause of the problem, document the changes made and supply copies of every changed file.

Please include:

- Relevant experience with PHP and PHPMailer
- Experience with Google Workspace SMTP and App Passwords
- Experience with Google reCAPTCHA v2
- Your estimated completion time
- Your fixed-price quotation