The errors below occur if you are using a different google play services version package from the one provided with the mediation package. Unity editor expects a dll to have the same name as it’s assembly, but it is not the case with these packages. While we recommend using the package included with mediation, you can patch this issue by renaming the dll mentioned, removing the version from its name. In the example above, Google.IOSResolver_v1.2.166.dll should be renamed to Google.IOSResolver.dll.
Assembly 'Assets/ExternalDependencyManager/Editor/Google.IOSResolver_v1.2.166.dll' will not be loaded due to errors:
Assembly name 'Google.IOSResolver' does not match file name 'Google.IOSResolver_v1.2.166'
For more information, see documentation on Unity Mediation.