1. Environment

Item	Details
Hosting	Hostinger (Open-/LiteSpeed stack)
WordPress	8.6.1
Amelia	Latest build (Step-by-Step Booking, Events Calendar, Catalog, etc.)
PHP limits	upload_max_filesize = 2048 M, post_max_size = 2048 M
Server cache	LiteSpeed Cache disabled during tests
ModSecurity	Temporarily disabled via SecFilterEngine Off / SecFilterScanPOST Off

2. Issue

Any Amelia form that contains the Attachment custom field fails to reach the final “Thank-you” page when the uploaded file is larger than ≈ 200 KB.

Effects:

• Booking is created in the back-end and file is stored.

• Front-end wizard freezes; no redirect or success screen.

Occurs in all Amelia modules (Step-by-Step, Events Calendar, Catalog, etc.).

3. How to reproduce

1. Add an Attachment field to any Amelia event or service.

2. On the front-end, upload a file < 200 KB → works.

3. Upload a file > 200 KB → wizard hangs (booking still saved).

4. What we see in DevTools

Case	Response from admin-ajax.php?action=wpamelia/api/booking
Success (< 200 KB)	HTTP 200 + valid JSON
Failure (> 200 KB)	HTTP 200 but body = corrupted binary / garbled characters.

The next /success request is never made when failure.

5. Troubleshooting already done

• Raised PHP limits (see §1).

• Disabled LiteSpeed Cache completely → no change.

• Disabled ModSecurity via .htaccess → no change.

• Same result across different browsers.

6. Help needed

1. Why does the JSON response become corrupted for files > ~200 KB?

2. Is there any Amelia buffer/attachment handling that could leak binary data into the AJAX response?

3. Recommended server settings (LiteSpeed / Hostinger) to let larger files pass?

4. Road-map: will front-end file-size validation or a “Max file size” setting be added soon?

Screenshots of both responses and current PHP info are ready to share.

Thank you for your assistance!