IL2CPP build connection error

[francescoStrada]

Configuration:
Windows 10
Unity: 2020.3.47f1
Build: IL2CPP, .NET 4x

I am facing a problem when building in a IL2CPP configuration as I receive a FormatterNotRegisteredException when I attempt to connect to the PupilCapture software. The same problem does not happen when the build is a "standard" Mono. I attach below the full error message (for better readability i also attach the actual log file, the error is at the end of the file).
This error is the SAME as if I would leave the API Compatibility Level to .NET Standard 2.0

Do you know how to avoid the issue and correctly establish the connection also in a IL2CPP build?

pupil-error.txt
FormatterNotRegisteredException: System.Collections.Generic.Dictionary2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.Object, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]] is not registered in this resolver. resolver:StandardResolver at MessagePack.FormatterResolverExtensions.GetFormatterWithVerify[T] (MessagePack.IFormatterResolver resolver) [0x00000] in <00000000000000000000000000000000>:0 at MessagePack.MessagePackSerializer.Serialize[T] (T obj, MessagePack.IFormatterResolver resolver) [0x00000] in <00000000000000000000000000000000>:0 at PupilLabs.RequestController+Request.SendRequestMessage (System.Collections.Generic.Dictionary2[TKey,TValue] data) [0x00000] in <00000000000000000000000000000000>:0
at PupilLabs.RequestController.Send (System.Collections.Generic.Dictionary`2[TKey,TValue] dictionary) [0x00000] in <00000000000000000000000000000000>:0
at PupilLabs.RequestController.Connected () [0x00000] in <00000000000000000000000000000000>:0
at PupilLabs.RequestController+d__28.MoveNext () [0x00000] in <00000000000000000000000000000000>:0
at UnityEngine.SetupCoroutine.InvokeMoveNext (System.Collections.IEnumerator enumerator, System.IntPtr returnValueAddress) [0x00000] in <00000000000000000000000000000000>:0

[erickson656]

I just had the same issue in:
Windows 10
Unity 2021.3.22f1
Build: IL2CPP, .NET Framework

It was a bit elusive, since I was able to build and run the project just fine, but was confused as to why my eye tracking recordings weren't showing up when they previously worked in the editor. For me, switching from IL2CPP to Mono fixed the issue.