Unable to Update Data Source Credentials

Hi,

I have a report that was created by someone who is no longer with my company.  This report uses Data Sources from Snowflake as well as an Excel Worksheet that is saved on a Network Drive.  This report began failing to refresh recently with the error:

Scheduled refresh is disabled because at least one data source is missing credentials. To start the refresh again, go to this dataset's settings page and enter credentials for all data sources. Then reactivate scheduled refresh.

This is normally fine, as we will go in and manually update the Data Source Credentials but recently we've become unable to.  When I navigate to the Data Source's Settings page, the Data Source Credentials option is greyed out - I can't expand it or even look at it:

I've tried refreshing the report locally and republishing, but the problem persists.  I've tried deleting the data source form the web app and republishing, but the problem persists.  I've tried clearing all credentials from the report in Desktop and republishing, but the problem persists.

Does anyone have any clue what could be causing this or how to resolve this problem?