Amazon AWS issues in Unity 5.5 on iOS!

Hey all,

Having an issue with my AWS integration on iOS- It keeps throwing the following error:

 MissingMethodException: Method not found: 'Default constructor not found...ctor() of Amazon.Util.Internal.PlatformServices.NetworkReachability'.
   at ThirdParty.iOS4Unity.Selector.get_Handle () [0x00000] in <filename unknown>:0 
   at System.Activator.CreateInstance (System.Type type, Boolean nonPublic) [0x00000] in <filename unknown>:0 
   at System.Activator.CreateInstance (System.Type type) [0x00000] in <filename unknown>:0 
   at Amazon.Util.Internal.PlatformServices.ServiceFactory..ctor () [0x00000] in <filename unknown>:0 
   at Amazon.Util.Internal.PlatformServices.ServiceFactory..cctor () [0x00000] in <filename unknown>:0 
   at Amazon.Util.Internal.InternalSDKUtils.BuildUserAgentString (System.String serviceSdkVersion) [0x00000] in <filename unknown>:0 
   at Amazon.CognitoIdentity.AmazonCognitoIdentityConfig..cctor () [0x00000] in <filename unknown>:0 
   at System.Nullable.GetUnderlyingType (System.Type nullableType) [0x00000] in <filename unknown>:0 
   at Amazon.CognitoIdentity.AmazonCognitoIdentityClient..ctor (Amazon.Runtime.AWSCredentials credentials, Amazon.RegionEndpoint region) [0x00000] in <filename unknown>:0 

Now, I've seen quite a few posts about this and the answer is always to create a link.xml file and drop it in Assets. Mine looks like this:

  <linker>
  
  <assembly fullname="UnityEngine">
      <type fullname="UnityEngine.Experimental.Networking.UnityWebRequest" preserve="all" />
      <type fullname="UnityEngine.Experimental.Networking.UploadHandlerRaw" preserve="all" />
      <type fullname="UnityEngine.Experimental.Networking.UploadHandler" preserve="all" />
      <type fullname="UnityEngine.Experimental.Networking.DownloadHandler" preserve="all" />
      <type fullname="UnityEngine.Experimental.Networking.DownloadHandlerBuffer" preserve="all" />
  </assembly>
  
  <assembly fullname="mscorlib">
      <namespace fullname="System.Security.Cryptography" preserve="all"/>
  </assembly>
  
  <assembly fullname="System">
      <namespace fullname="System.Security.Cryptography" preserve="all"/>
  </assembly>
  
  
  <assembly fullname="AWSSDK.Core">
      <type fullname="Amazon.Util.Internal.PlatformServices.NetworkReachability" preserve="all"/>
     <namespace fullname="Amazon.Util.Internal.PlatformServices" preserve="all"/>
  </assembly>
  <assembly fullname="AWSSDK.CognitoIdentity">
     <type fullname ="Amazon.*" preserve = "all" />
     <namespace fullname="Amazon.Util.Internal.PlatformServices" preserve="all"/>
  </assembly>
  <assembly fullname="AWSSDK.SecurityToken">
     <namespace fullname="Amazon.Util.Internal.PlatformServices" preserve="all"/>
  </assembly>
  <assembly fullname="AWSSDK.DynamoDBv2" preserve="all"/>
  
  </linker>

A few weird things- I can't see the XML file in my project directory. Is that normal? Additionally, this does not seem to fix the issue! Tips/hints?