A layer in your document is using an XY event table as a data source, which can perform slowly in many situations.
Check the drawing performance for your layer or basemap layer in ArcMap. If you are publishing, check the drawing performance for your service in the Preview window.
XY event data sources are commonly used to draw point data originating from a data source that is not spatially enabled. In this respect, XY event data sources are a powerful way to integrate simple point data into your map. However, the simplicity of this integration comes with a cost in that XY event sources cannot take advantage of spatial indexing that makes spatial data sources perform well. Consider converting your data to a spatial data source such as a file geodatabase or enterprise geodatabase. If the data resides in a relational database that cannot be geodatabase enabled, consider using the database's native spatial storage type and drawing it with a query layer as an alternative to XY events.