New Woocommerce activation kit with XLS Padlock 2026.3 - Error HTTP 500

Hello,

I updated Xls Padlock to the latest version, 2026.3. After creating a new protected workbook, I noticed that the connection to the server for license activation no longer works.

I receive the following error:

"The license server could not be reached (HTTP 500). Please try again later."

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Note that I have not yet updated the WooCommerce integration kit to the latest version.

My question is: if I update the WooCommerce activation kit to the latest version, will all existing protected Excel workbooks stop working? Will they all receive this same error?

Thank you,

Marco D.P.

Did any other user encountered the same issue?

The cause was found: there was an error in the workbooks.json file. For anyone who gets the same "The license server could not be reached (HTTP 500)" message, this file is the first thing to check.

To answer your question for other readers: updating the WooCommerce Integration Kit does not break existing workbooks. The 2026 kit still recognizes the requests of workbooks built with earlier versions of XLS Padlock, and of workbooks built with 2026.3 while the option "Compatibility mode for pre-2026 activation kits" is checked, which is the default. It answers each of them in the format it expects. When you update, keep your inc/lib/validationkey.txt, inc/config.ini and inc/workbooks.json files.

There is one other known cause of an HTTP 500 at activation: kits older than version 2026.1 running on PHP 8.5. In that case, the server's PHP error log shows "Function curl_close() is deprecated", and updating to the WooCommerce Integration Kit 2026.1, available from your account, fixes it.