Thank you for joining the thread, @dadan. Allow me to clear things up for you about importing Web Connect files in QuickBooks Desktop (QBDT).

The Web Connect feature requires a supported version of QBDT. The 2018 and older versions no longer have this type of service available for them. See this article for additional information about discontinued products: QuickBooks Desktop service discontinuation policy and upgrade information. 

If you decide to upgrade your QBDT version and continue to see errors during the Web Connect process, keep this article for reference: Fix Web Connect import errors. 

Post a reply if you have other questions about Web Connect in QBDT. I'll get back to you as soon as I can. Have a great day!