What to do if it says: "Unable to create a new security page for the stack"?

Question

WPF

Wrote a small C# wpf application. I launch the application, then I need to enter in the textbox what is written in the textblock. If it is entered correctly (the condition is written in the code), a new word appears in the textblock, if not, then a new word still appears. If you remove the condition on the incorrectness of the textbox, then the signs where it says "Unable to create a new protection page for the stack" do not appear