Hi Frank,
So I looked into this a little more and I was able to get it working. After adding the service in ArcMap, I noticed that the time slider was using 1 year intervals on January 1st of each year. After going into the time slider settings in the ArcGIS.com map viewer > Advanced options, I set the start and end time to January 1st and changed the option to display the data in 1 year intervals and this seemed to work.
I also noticed that the time slider goes all the way back to 1927 but the first year with data is 2013 with data going all the way to 2023.
One other side note; when using firefox I had to add the certificate for your ArcGIS Server as an exception to my browser since you have SSL enabled but did not need to do this for IE or for Chrome.
Let me know if this resolves your issue,
Daniel, S.