This map has been shared publicly, yet I see a "sign into ArcGIS Online" popup?https://agresearch.montana.edu/warc/research_current/msu-ext-fruit-research-sites/test.html
Can you ask this Q in ArcGIS Online forum: https://community.esri.com/community/gis/web-gis/arcgisonline
I am guessing one of the layers you are using is either not public or is a premium service that would require you to login against.
