I have a nintex form which has an attachment field

The form is showing that maximum allowed size if 2047 MB.

I am uploading attachment of size 25 MB and then I submit the form.

After clicking on the submit the item "Submission" is not created in my list and I am not getting any error message ... the system just directs me to the homepage.

I tried to use the front end server url and upload the same attachment and it worked fine.