Hello Karl,
It’s me again… 
I’ve finished implementing localization, all my text is working on PC (about 70% fine, I’ll explain later), but now I’m trying to use it on mobile, as my game is for Android.
I haven’t found any extra step that was needed to make it work on mobile, so I just followed the tutorials, the problem is that the language won’t change, I’m getting this error:
10-30 18:50:39.853 14971 27703 E Unity : MissingMethodException: Default constructor not found for type UnityEngine.ResourceManagement.ResourceManager+CompletedOperation`1[[System.Collections.Generic.IList`1[[UnityEngine.Localization.Locale, Unity.Localization, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null]], mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]]
10-30 18:50:39.853 14971 27703 E Unity : at System.RuntimeType.CreateInstanceMono (System.Boolean nonPublic) [0x00000] in <00000000000000000000000000000000>:0
10-30 18:50:39.853 14971 27703 E Unity : at System.Activator.CreateInstance (System.Type type, System.Boolean nonPublic) [0x00000] in <00000000000000000000000000000000>:0
10-30 18:50:39.853 14971 27703 E Unity : at UnityEngine.ResourceManagement.Util.LRUCacheAllocationStrategy.New (System.Type type, System.Int32 typeHash) [0x00000] in <00000000000000000000000000000000>:0
10-30 18:50:39.853 14971 27703 E Unity : at UnityEngine.ResourceManagement.ResourceManager.CreateOperation[T] (System.Type actualType, System.Int32 typeHash, UnityEngine.ResourceManagement.Util.IOperationCacheKey cacheKey, System.Action`1[T] onDestroyAction) [0x00000] in <00000000000000
Found it using the command prompt and using: Unity\Hub\Editor\2020.3.6f1\Editor\Data\PlaybackEngines\AndroidPlayer\SDK\tools>adb logcat Unity: D *:S
Here’s a pic to better ilustrate what happens every time I click the button that was supposed to change the language.
And here’s the function the button calls:
public void SetLocale(Locale locale)
{
LocalizationSettings.SelectedLocale = locale;
m_InitializeOperation = LocalizationSettings.SelectedLocaleAsync;
}
Here’s my translation code, in case it helps:
public string Translate (string source)
{
LocalizedString stringComponent = new LocalizedString();
stringComponent.TableReference = "Revenot Localization";
stringComponent.TableEntryReference = source;
return stringComponent.GetLocalizedString();
}
And lastly, but not least, I said 70% of the times before, because on PC sometimes instead of translating the texts it shows a message “Loading…”, but it never loads, I have to stop the application and run it again to translate.
I know it’s a bit long this post, but I truly believe you can help me 
but I’m still getting the same error: