There are some users they are not able to submit the requests form portal through the catalog item. whenever they click on the Submit we are getting the error "Sorry you do not have an access or either data does exist can some help me with this why

[Mannam Praveen]

There are some users they are not able to submit the requests form portal through the catalog item. whenever they click on the Submit we are getting the error "Sorry  you do not have an access or either data does exist can some help me with this why we getting this error how to fix 

[Harish KM]

Did you check the options mentioned in this link?

https://support.servicenow.com/kb?id=kb_article_view&sysparm_article=KB0751522