Acrobat Pro DC add-on in Firefox does not convert to PDF

Hi,

Windows 10 Enterprise 1803, Acrobat Pro DC 2019.012.20040, Firefox 69.0, Acrobat Add-on 18.0.10

Hi,

When I try to convert a web page with the Acrobat Add-on in the upper right corner of my Firefox browser, I get an error message in Acrobat:

There was an error opening this document. This file cannot be found.

I cannot do anything else.

In Chrome I can convert to PDF without any problems.

Is there anything what I can do? Or is this a bug?

Thank you very much for your help!

Best regards

Winfried