This usually menas that either permission was lost in Metadata for the user or the folder in DAV that you are accessing is defined so you cannot write to it.
I would first try Validating the Content Server from SAS Management Console:
https://go.documentation.sas.com/?docsetId=bisag&docsetTarget=bisag.pdf&docsetVersion=9.4&locale=en
1. Log on to SAS Management Console as grcadmin, and expand the Server Manager node.
2. Right-click the SAS Content Server node and select Validate.
SAS Management Console attempts to make a WebDAV connection to the server. If the connection is successful, the following message is displayed:
Validation Successful!
This message indicates that a WebDAV server is listening on the specified host and port, and that the first configured base path exists on the server.
If the connection is not successful, an error message is displayed.
If Validation works then try using the SAS Content Server Administration Console or DAVTree interface to get to the folder as grcadmin. What do you see? Is the folder read only? Is it owned by grcadmin or sasadm@saspw?