What Does Procedural Grounds Mean in Legal Contexts?

[askingquestion]

What is the meaning of the expression procedural grounds in the text:
Butler attended Boise State University for a year.[9] In 1991, Butler was convicted of assault during his freshman year of college.[5] His appeal was unsuccessful on procedural grounds, as a judge ruled that Butler's defense attorney did not raise the issue in an earlier appeal. The Idaho State Penitentiary paroled Butler on 26 April 1995.[10]
?
From: https://en.m.wikipedia.org/wiki/Max_Butler
I an not native English so I need explanation please.

 

[berkeman]

I think you already asked this question and received answers, no?

Butler attended Boise State University for a year. In 1991, Butler was convicted of assault during his freshman year of college. His appeal was unsuccessful or procedural grounds, as a judge ruled that Butler's defense attorney did not raise the issue in an earlier appeal. The Idaho State Penitentiary paroled Butler on 26 April 1995.

What is the meaning of procedural ground?
(I am not English Native, so I need explanation).
Thank you in advance.

 

[askingquestion]

Yes. Please delete it. Sorry.

 

[askingquestion]

How can I the see the orginal question.

 

[berkeman]

How can I the see the orginal question.

Click the little up-arrow symbol in the upper left of the quote box that I posted. That takes you to that quote in your previous thread. This duplicate thread is now closed.