I am new to Unreal Engine. And I was also receiving this error with version 5.6 but only on creating a project with C++ instead of selecting Blueprints.
So, I unchecked (disabled) “Load last project at Startup” and now it loads without errors when I open the project from the Recent Projects list within Unreal Engine.
Not sure if that’s a valid solution to this problem, or not, and I’m not sure why the error only appears when “Load last project at Startup” is enabled.
I tried everything to fix this problem from all the suggestions on this post, and nothing worked for me until I disabled load project at startup.