Too many WebGL contexts. Unable to add the layer

Error Message

After adding sixteen maps to an ArcGIS Insights page using a vector tile basemap, when attempting to add a seventeenth map, the map does not load, and it may be necessary to delete the files from your AppData folder if Insights stops working. The JavaScript API throws the error:

 Too many WebGL contexts. Unable to add the layer

Cause

The 3.x version of the JS API creates one WebGL context per vector tile layer added to a workbook, and Chromium has a limit of sixteen WebGL contexts. Mobile browsers have a limit of eight WebGL contexts.

Solution or Workaround

Use a raster basemap, rather than a vector tile basemap.

Additionally, the 4.x version of the JS API utilizes WebGL contexts differently so that this limit will not be reached as quickly. Consider creating a map in the new Map Viewer, or create an Instant app or web experience instead of using Web AppBuilder.