I can not change the unique symology using AGOL, attached a picture with the problem.
Thank in advance any help
I've moved your post into the Arcgis Online space. You will get a much better answer here as the GeoNet Help is intended for community help and feedback. I have also added in a few additional tags. You can see more on the community structure, and what topics are under each space from the following documents:
GeoNet Community Structure
ArcGIS Discussion Forums Migration Strategy
Retrieving data ...