diff --git a/src/pretix/base/datasync/datasync.py b/src/pretix/base/datasync/datasync.py
index 34c2e96604..6bdaab857f 100644
--- a/src/pretix/base/datasync/datasync.py
+++ b/src/pretix/base/datasync/datasync.py
@@ -223,7 +223,10 @@ class OutboundSyncProvider:
 
     def get_field_value(self, inputs, mapping_entry):
         key = mapping_entry["pretix_field"]
-        required_input, label, ptype, enum_opts, getter = self.data_fields.get(key)
+        try:
+            required_input, label, ptype, enum_opts, getter = self.data_fields[key]
+        except KeyError:
+            raise SyncConfigError(['Field "%s" is not valid for %s. Please check your %s settings.' % (key, "/".join(inputs.keys()), self.display_name)])
         input = inputs[required_input]
         val = getter(input)
         if isinstance(val, list):
@@ -271,7 +274,7 @@ class OutboundSyncProvider:
 
     def sync_order(self, order):
         if not self.order_valid_for_sync(order):
-            logger.debug("Skipping order (not valid for sync)", order)
+            logger.debug("Skipping order %r (not valid for sync)", order)
             return
 
         logger.debug("Syncing order %r", order)
diff --git a/src/pretix/control/logdisplay.py b/src/pretix/control/logdisplay.py
index a7dd8aaa88..4160c716bc 100644
--- a/src/pretix/control/logdisplay.py
+++ b/src/pretix/control/logdisplay.py
@@ -438,7 +438,7 @@ class OrderDataSyncLogentrytype(OrderLogEntryType):
                         if obj and 'external_link_href' in obj and 'external_link_display_name' in obj
                     ))
 
-        return mark_safe(super().display(logentry, data) + "".join("<p>" + link + "</p>" for link in links))
+        return mark_safe(escape(super().display(logentry, data)) + "".join("<p>" + link + "</p>" for link in links))
 
 
 @log_entry_types.new_from_dict({
@@ -449,7 +449,7 @@ class OrderDataSyncErrorLogentrytype(OrderLogEntryType):
         errmes = data["error"]
         if not isinstance(errmes, list):
             errmes = [errmes]
-        return mark_safe(escape(self.plain) + "".join("<p>" + escape(msg) + "</p>" for msg in errmes))
+        return mark_safe(escape(super().display(logentry, data)) + "".join("<p>" + escape(msg) + "</p>" for msg in errmes))
 
 
 @receiver(signal=logentry_display, dispatch_uid="pretixcontrol_logentry_display")