System.TypeInitializationException - ZeroFormatterEqualityComparer on Android

[philipogorman]

I get the error below when deserializing on android . The code is in a net standard 2 library, the file deserilaizes fine in a net core unit test runner.

The data type is:
Dictionary<int, Dictionary<string, Dictionary<string, SimpleObject>>>

Unhandled Exception:

System.TypeInitializationException: The type initializer for 'ZeroFormatter.Comparers.ZeroFormatterEqualityComparer`1' threw an exception. occurred


at ZeroFormatter.Formatters.DictionaryFormatter`3[TTypeResolver,TKey,TValue].Deserialize (System.Byte[]& bytes, System.Int32 offset, ZeroFormatter.DirtyTracker tracker, System.Int32& byteSize) [0x00025] in <be1feee373484d2195f08309177a3679>:0 
  at ZeroFormatter.ZeroFormatterSerializer+CustomSerializer`1[TTypeResolver].Deserialize[T] (System.Byte[] bytes) [0x00034] in <be1feee373484d2195f08309177a3679>:0 
  at ZeroFormatter.ZeroFormatterSerializer.Deserialize[T] (System.Byte[] bytes) [0x00000] in <be1feee373484d2195f08309177a3679>:0 

Any ideas what could be wrong?