invalid window error

[N8RzwA7f]

Hello,

I have a c++/sdl2 program.
I have declared several vectors in one class (type SDl_Texture* )
and all was well.
wanted to declare one more of the same type and got the
invalid window SDL error and the program crashes.
as far as I know there is no name conflicts going on. I tried with different names for this declaration and got the same result. If I remove this one declaration the program works fine.
I wanted to add this one vector to add something to the program , it works fine otherwise.

so why is this happening?

thanks.