Hi,
I understand that you're unable to install your Microsoft Office Professional Plus 2019. I can imagine how inconvenient this must be on your end. Don't
worry, let me assist you.
There are a lot of reasons why this issue is happening. One, you're product key is a potential concern. Two, the previous version of the Office suite
can also be a factor. Your internet connection is causing the server error. To correct this issue, you can clarify the product key to the store where you have purchased the program. Two you can check this link about uninstalling Office
on your PC. Three, use a different web browser to do the process again.
Let us know how it goes.
Bob