sharepoint online not firing button click events in asp.net application using inside iframe

Hello, I am using sharepoint online version and i created a webpage and inside that using web part and added Embed to use iFrame to call the asp.net application. 

the page shows up inside of web part when i view it, but in that application, it has backend vb.net code behind for searching information, when the buttons are clicked it is throwing application errors. 

vb.net application is serving aspx pages with vb.net code behind.

<asp: Button ID="Button1" runt="server" Text="Search" /> when it is clicked i get runtime error. 

Is there something in SharePoint online that i have to turn on or off for this to work?