First you need to go to my github repository [login to view URL]
I Create a single app in xamarin forms, than send a basic information to the server, en the project you will see the Backend/controller/Api/Reactions,
here is where you need to fix, because I dont know what the hell is going on, it supposed to reseive from body a class of type ReactionResponse, but it give internal server error, you just need to fix this sending a pull request or sending me the code to check it,
I guess than to an expert it will take less than 20 minuts, having in mind than the hours normal is 10-15, i will paid 15 to fix this issue. 20 if you complete the put and the delete than are comment it right now :)
RIGHT NOW yes i will fix it Develop Web Application Product,UI layout, SPA with Angularjs,HTML5,CSS3, Bootstrap,MVC or MVVM pattern and resolve all issues & bugs with Agile Methodology.