I have removed the second image you posted because it includes your confidential serial key which should never be posted to a public forum like this one. To do so is to risk your software being hijacked. You do not need to prove to we fellow-users that you have purchased the software!
It is not entirely clear at what point in the installation process you see the error message. Can you clarify that, please? The file you list is the Download Manager for Photostory, whose purpose is to download all the files needed for the app to be installed and, once that is completed, to actually run the installer. Those installation files, by default, should be saved to C:\Users\[your user name]\Documents\MAGIX Downloads. Are the files there? If so, you can run the installer (which will have a name something like) Photostory_deluxe_2023_188.8.131.52_DLV_INT_220831_16-46_E4F98976_22_0_3_135.exe Yours will be different because this is the name of the installer which I used some weeks ago now but it should be substantially similar.
Sorry, I thought I was adressing directly the Magix support and not an open forum. I managed to download the file photostorydeluxe2023_dlm_eiodxy.exe, which is only 6355 Kb in size. I suppose the remaining of the software would be downloaded after that, but then the error message appears. I am running a 64 bits Windows 10, with 16 GB RAM, in a AMD Ryzen 5 300G with Radeon Vega Graphics, at 3,70 GHz. I have AVAST Premium installed.
As an initial thing to check, fully turn off your Avast Premium before you begin the installation. A considerable number of users have experienced similar problems, caused by "over-eager" protection by their antivirus and/or firewall!
If the installation now succeeds, don't forget to then turn Avast back on!