With the current version of the Wikitude Unity Plugin (1.0.0) there is a known issue when running it on an Android 64 bit phone. This issue will be fixed in the next Unity release, what you can do for now is the following:
Change the file extension of the aar file under Assets/Plugins/Android from ".aar" to ".zip" and extract it
Delete the folder lib/arm64-v8a
If your archiving tool created a new folder when extracting, zip only the contents of this folder and now rename the extension of the file from ".zip" to ".aar"
Use this new aar instead of the old
over 2 years ago
Version 1.0.1-1.0.0 of the Unity plugin fixes the 64-bit issue, so the workaround is not needed anymore.