HI Student Student and Helen Yang,
I had the same issue on the ArcGIS Enterprise 10.7.1 (Portal, ArcGIS, and DataStore on different machines) after updates the new DNS name on ArcGIS and Portal for ArcGIS servers.
my relational datastore has an issue that has the same error message. but no other tiled cache datastore.
The steps I took that solves my issues :
1. un-register the relational datastore from ArcGIS Manager
2. run the command in the Datastore machine
- Go to datastore installed location on the machine. eg. c:\Program Files\ArcGIS\DataStore\tools>
- register the datastore using the command below
registerdatastore https://arcgisserver:6443/arcgis/admin arcgissiteadmin arcgissiteadmin_password --stores relational
(more details please refer to the URL ArcGIS Data Store command utility reference—ArcGIS Data Store (Windows) Installation Guide | ArcGIS ... )
Please note to do all the backup before making further changes if it's a production environment. (my scenario that all the items in datastore are retains).
~Vicky Wang~