I have all the time a problem like this and I have C/C the source file of the tutoriel. How can I solve this? And the best is, when I try to just create a class I have this bug.
I have try to uninstall UE4, reboot my PC, set up a new version of Windows and I have this problem.
Does the error you show in the image prevent you from being able to build your project? It looks like an Intellisense error, and Intellisense will sometimes indicate errors where there actually are none.
Just try building it. Like @ has said, this error might be coming from intellisense. Intellisense seems to perform better after a build is completed. So just go ahead and build the project.
If your build succeeded, then there is nothing to worry about. Intellisense is known to have some issues or delays with UE4 projects. As long your builds are passing, you have nothing to worry about.