diff --git a/bin/weewx/tags.py b/bin/weewx/tags.py
index cdc8385a..57812196 100644
--- a/bin/weewx/tags.py
+++ b/bin/weewx/tags.py
@@ -482,7 +482,12 @@ class AggTypeBinder(object):
 
     def _do_query(self):
         """Run a query against the databases, using the given aggregation type."""
-        db_manager = self.db_lookup(self.data_binding)
+        try:
+            # Get the appropriate database manager
+            db_manager = self.db_lookup(self.data_binding)
+        except weewx.UnknownBinding:
+            # Don't recognize the binding.
+            raise AttributeError(self.data_binding)
         try:
             # If we cannot perform the aggregation, we will get an UnknownType or
             # UnknownAggregation error. Be prepared to catch it.
diff --git a/bin/weewx/tests/expected/StandardTest/index.html b/bin/weewx/tests/expected/StandardTest/index.html
index ccf9d446..8b791ee5 100644
--- a/bin/weewx/tests/expected/StandardTest/index.html
+++ b/bin/weewx/tests/expected/StandardTest/index.html
@@ -506,6 +506,10 @@
       <td>Max Temperature in alt_binding</td>
       <td>25.1&#176;F</td>
     </tr>
+    <tr>
+      <td>Max Temperature with bogus binding</td>
+      <td>$day($data_binding='foo_binding').outTemp.max</td>
+    </tr>
     <tr>
       <td>Min temp with explicit conversion to Celsius</td>
       <td>3.8&#176;C</td>
diff --git a/bin/weewx/tests/expected/StandardTest/metric/index.html b/bin/weewx/tests/expected/StandardTest/metric/index.html
index 53ddee96..6677e496 100644
--- a/bin/weewx/tests/expected/StandardTest/metric/index.html
+++ b/bin/weewx/tests/expected/StandardTest/metric/index.html
@@ -506,6 +506,10 @@
       <td>Max Temperature in alt_binding</td>
       <td>-3.9&#176;C</td>
     </tr>
+    <tr>
+      <td>Max Temperature with bogus binding</td>
+      <td>$day($data_binding='foo_binding').outTemp.max</td>
+    </tr>
     <tr>
       <td>Min temp with explicit conversion to Celsius</td>
       <td>3.8&#176;C</td>
diff --git a/bin/weewx/tests/test_skins/StandardTest/index.html.tmpl b/bin/weewx/tests/test_skins/StandardTest/index.html.tmpl
index ea01caf3..8309bc11 100644
--- a/bin/weewx/tests/test_skins/StandardTest/index.html.tmpl
+++ b/bin/weewx/tests/test_skins/StandardTest/index.html.tmpl
@@ -506,6 +506,10 @@ FALSE#slurp
       <td>Max Temperature in alt_binding</td>
       <td>$day($data_binding='alt_binding').outTemp.max</td>
     </tr>
+    <tr>
+      <td>Max Temperature with bogus binding</td>
+      <td>$day($data_binding='foo_binding').outTemp.max</td>
+    </tr>
     <tr>
       <td>Min temp with explicit conversion to Celsius</td>
       <td>$day.outTemp.min.degree_C</td>
diff --git a/docs/changes.md b/docs/changes.md
index c2af064c..94ceba05 100644
--- a/docs/changes.md
+++ b/docs/changes.md
@@ -49,6 +49,9 @@ user jocelynj! PR #842.
 Fix problem that prevented wee_device --set-retransmit from working on
 Vantage stations.
 
+Using a bad data binding with an aggregation tag no longer results in an
+exception. Instead, it shows the tag in the results. Related to PR #817.
+
 
 ### 4.10.1 01/30/2023