Could you check if your basemap supports offline? Here is some help doc might help
Prepare for offline data collection—ArcGIS Collector | Documentation
Hello,
Thank you very much for your answer I will look.
On the other hand, I thought that by publishing the feature layer with these criteria, I should see the properties window if I could activate the offline mode or not. Is it after the publication?
Were you able to resolve the issues you were having? I've been going through the documentation and I'm finding the process confusing to set up a layer for editing in ArcGIS Collector offline. I haven't figured it out yet
I too am currently trying to use disconnected/offline editing with Collector via editable layers published thru my organizational Portal. I've read thru some of the ESRI docs on preparing data for offline editing and preparing maps for offline editing. My data is registered as versioned; editing capabilities are all checked on when publishing; I add the feature layer to a Portal WebMap; the WebMap has the "use in Collector" checkbox checked on under the settings. However, when I open Collector (Desktop or iPad) and click on the 3-dot ellipsis next to the map, only the "details" option is available. There is no longer a "download area" option. I haven't attempted to do this in maybe 8 months or so but the last time I tried, I had no problem downloading an area for offline editing.
Any thoughts? Thanks!