I made a custom form. After submitting you are redirected to a custom page and get a message there. So far nop.
Then I made a custom block that renderw this form into a block region. Everything appears well.
However when submitting this same form, no redirection. I am on localhost and suspect that the form is not submitting in this block. After submit I see all values in the url of my page, just like the method is GET. When I check the code the method is POST, just like the original form, also Drupal added some classes which are the same as in the form.