June 2026 Update - Map Viewer Add Layer Not Working

[JeremyBrown4]

After the most recent update to ArcGIS Online I have not been able to add a layer to a map using the "Add layer" function in Map Viewer. I am still able to add layers via URL, but not using the "Add" button at the bottom of the layer list. Is anyone else seeing this issue, or know of a simple solution. Clearing browser cache did not work.

[DebapriyaPaul]

Hi @JeremyBrown4 , thanks for posting the question. To investigate into the issue, 

• Which browser are you using? Do you see the same issue using a different browser?
• Do you see any errors in the browser developer tools when you click on the Add button? 
• Do you experience the same issue when you click on the Contents (dark) toolbar > Add > Browse layers? 

[JeremyBrown4]

• I'm using Chrome as my browser. I tested in Edge and it works fine there.
• Console shows this error when I click Add. "GET: 431 (Request Header Fields Too Large)"
• Same issue when I use Contents (dark) toolbar > Add > Browse layers

[JonathanMcD]

@JeremyBrown4 

This sounds so obvious, but I'll say it anyway. After every update I communicate to users that it's really important that they delete their browser caches to lessen any possible issues. The browser I use for AGOL is actually set to delete cache etc on close.

[DebapriyaPaul]

Thanks for sharing more details, @JeremyBrown4.

Are you accessing ArcGIS Online from a bookmark in the browser? Or are you signed into a different ArcGIS Online organization when this reproduces? Do you replicate the same behavior using an incognito window in Google Chrome?