It’s not letting me to export my file. There’s always an error saying “unable to export.” Please help

Which version of Audacity? (look in “Help menu > About Audacity”)
Which version of Windows?

Where are you trying to export to?
What name are you trying to use for the exported file?
Has the Audacity project been saved?
Does the Audacity project contain imported files, a new recording, or both?