How to fix not showing button Notify Me on M2.2.1?

QUESTION:

I install the module Bss_OutofStockNotification version 1.2.6 on my Magento2.2.1 but it doesn't show the button Notify Me after successful installation.

I consume that the module is not compatible with M2.2.1.

Do you have any solution available?

ANSWER:

Please edit the file app/code/Bss/ProductStockAlert/Controller/Ajax/FormData.php as below:

Or download the file attached below to override the current file on your site.

If you need any further assistance, please feel free to contact us. We'd be happy to support!