I'm getting the above error message. However, the page in question does indeed have a tag with runat="server" attribute on it (at design time) and the control
progress-bar
ruby-watir
alphabetic
splitinstallmanager
dayjs
penn-treebank
storing-data
image-rs
hal-json
polygons
malloc
v8js
tensorflow-quantum
pspad
react-native-video
forward-indexing
structured-array
feathericons
pageable
angular4-forms
grafana-dashboard
angular-google-maps
angular-lifecycle-hooks
acumatica-kb
zimbra
spyne
dropbox-sdk
scalariform
osmand
serverside-datatable