Error with Invoice button in order when PDF invoice plugin is installed

-- url of the page with the problem -- : -
-- HikaShop version -- : 3.1.1
-- Joomla version -- : 3.7.5
-- PHP version -- : 7.0
-- Browser(s) name and version -- : all
-- Error-message(debug-mod must be tuned on) -- : The tag does not yet exist.

I recently installed the PDF attachment plugin for my customers. However, when I now use the "Invoice" button within the order, an error is generated, see screenprint:



The error remains when I disable the plugin.

Hi,

First, I don't see how the error would persist with the plugin disabled.
So in that case, it must be some caching of your browser doing that after disabling the plugin.

Also, that error message indicates that you've added script tags in the file plugins/hikashop/attachinvoice/attachinvoice/invoice.php
and that is not valid for HTML2PDF, the library used to convert the HTML of the invoice into a PDF.
So please check on that.

I definitely did not make any changes in code. However, I started troubleshooting the issue on a test-copy of my site and there were no issues there, so it may be related to something in my hosting environment, though they have the same PHP version.
I will do some troubleshooting myself first.