May 30, 2020 05:01 PM|jzero|LINK
Just a guess.
Seems at some point you don´t have UserID defined, perhaps in page load.
Be sure you have UserID already set on page load other than SQLDataSource will not return any record, this way there will no records rendered on gridview.
When you click on paging, looks UserID is defined then Gridview.Dababind does the job.
If I´m correct even pushing Gridview.DataBind on Page Load, there will be no records on Gridview