diff --git a/src/main/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidder.java b/src/main/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidder.java
index 99f5eda1ec2..e047a077599 100644
--- a/src/main/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidder.java
+++ b/src/main/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidder.java
@@ -89,6 +89,11 @@ public Result<List<HttpRequest<BidRequest>>> makeHttpRequests(BidRequest request
             }
         }
 
+        if (StringUtils.isBlank(sourceSupplyId) && StringUtils.isBlank(supplyId)) {
+            return Result.withError(
+                BidderError.badInput("Either supplySourceId or a default endpoint must be provided"));
+        }
+
         final BidRequest outgoingRequest = modifyRequest(request, modifiedImps, publisherId);
         final HttpRequest<BidRequest> httpRequest = BidderUtil.defaultRequest(
                 outgoingRequest,
diff --git a/src/test/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidderTest.java b/src/test/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidderTest.java
index 021bca5617a..a292ac6d385 100644
--- a/src/test/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidderTest.java
+++ b/src/test/java/org/prebid/server/bidder/thetradedesk/TheTradeDeskBidderTest.java
@@ -186,6 +186,21 @@ public void makeHttpRequestsShouldReturnErrorWhenImpExtCouldNotBeParsed() {
         assertThat(result.getValue()).isEmpty();
     }
 
+    @Test
+    public void makeHttpRequestsShouldReturnErrorWhenBothSupplySourceIdAndSupplyIdAreNull() {
+        final TheTradeDeskBidder bidderWithNullSupplyId = new TheTradeDeskBidder(ENDPOINT_URL, jacksonMapper, null);
+        final BidRequest bidRequest = givenBidRequest(
+                identity(),
+                imp -> imp.ext(impExt("publisher", null)));
+
+        final Result<List<HttpRequest<BidRequest>>> result = bidderWithNullSupplyId.makeHttpRequests(bidRequest);
+
+        assertThat(result.getErrors()).hasSize(1);
+        assertThat(result.getErrors().getFirst().getMessage())
+                .isEqualTo("Either supplySourceId or a default endpoint must be provided");
+        assertThat(result.getValue()).isEmpty();
+    }
+
     @Test
     public void makeHttpRequestsShouldReturnSiteWithExtImpPublisherWhenSiteAndAppArePresent() {
         final BidRequest bidRequest = givenBidRequest(