diff --git a/briar-core/src/test/java/org/briarproject/briar/introduction/IntroductionIntegrationTest.java b/briar-core/src/test/java/org/briarproject/briar/introduction/IntroductionIntegrationTest.java
index 88e13b57a..dd980aa18 100644
--- a/briar-core/src/test/java/org/briarproject/briar/introduction/IntroductionIntegrationTest.java
+++ b/briar-core/src/test/java/org/briarproject/briar/introduction/IntroductionIntegrationTest.java
@@ -1057,6 +1057,7 @@ public class IntroductionIntegrationTest
 		sync1To0(1, true);
 		sync0To1(3, true);
 		sync1To0(2, true);
+		ack0To1(2);
 
 		// a new introduction should be possible
 		assertTrue(introductionManager0