If you were shown the following message on the request page: "You cannot send requests from your region" Unfortunately, you cannot send requests.
pixiv operates in strict compliance with laws, so based on the region of operation (by both the company and each community member), certain content may be subject to restrictions such as display restrictions if the content violates the law in the region from which the person is browsing.
For more information on your browsing location, please check the article below.
I can't browse certain works from the country/region where I live