The layer ... cannot be added to the map.

[JoannaCraigmile]

My public web map is all of a sudden incredibly slow to load.  I then get the following error:

I tried updating the data and it still says it cannot be added to the map.  

I get the same error if I just try to view these layers in the map viewer individually.  

These layers have been loaded thousands of times in the past with no error.

Where did my data go and how do I fix this?

Thanks.

[MarkQuattlebaum]

If your data had geometric networks data associated with it, AGOL’s latest update is the culprit. Sadly the answer is copy the data to a newly created database for each and every update you wish to accomplish and post your updates to AGOL from that newly created database AFTER you zip it. Just as sadly ESRI AGOL doesn’t care that they messed up a bunch of users.

[RhettZufelt]

You say you tried updating the  data, did you happen to overwrite web layer with Pro 3.0?

I overwrite my layer(s) fairly often with no issues.  Pro 3, however, broke about half the layers within my hosted feature layer.

Tried re-adding it to the maps, no go.  add to new map, no go.  Delete the hosted feature layer and service definition from AGOl and re-publish (share web layer from Pro) with same name, No Go.

Re-publish web layer from Pro with slightly different name, works fine.

Have used 2.9.3 to overwrite web layers since, no issues.

R_

No geometric networks, just FGDB FC's

[JeremyHolcombe]

I had the same problem this week. I cleared out my web browser cache and it began to cooperate. Hopefully that works for you.