I am working with SharePoint on prem 2019 and have a team site created in modern experience where several document libraries have been added. When site is accessed and document library link is clicked from quick launch, it opens up in modern UI. Once return to classic sharepoint is clicked, it takes to the classic experience. Once on the classic UI page, I do not see 'Exit Classic experience' link on the lower bottom left to go back to modern ui at all.
What could be the cause of this, can someone please assist, thanks in advance.