It looks like the issue is coming from the Snowflake Excel connector not receiving a valid warehouse/endpoint identifier when executing the query.

Since login and catalog browsing work fine, authentication is OK — the failure happens at query execution time, which usually points to one of these causes:

• The selected warehouse session context is not being passed correctly (blank/invalid warehouse ID)
• The worksheet/excel plugin session lost the warehouse binding after an update or session timeout
• The connector update changed how endpoint/warehouse IDs are resolved (this has happened in recent connector versions)

What you can try:

• Re-select the warehouse in the Excel plugin and reconnect (don’t rely on the previously selected one)
• Fully log out of the Excel plugin and log back in
• Restart Excel to clear cached session metadata
• Verify the warehouse is active and not suspended
• If multiple accounts/regions are used, ensure you're connected to the correct Snowflake account endpoint

If it started suddenly today, it’s very likely a session/connector-side issue rather than a SQL problem.

If the issue persists, checking the latest Excel connector version or reinstalling it often resolves this type of “invalid endpoint id” error.