diff --git a/src/test/kotlin/org/briarproject/briar/desktop/testdata/DeterministicTestDataCreatorImpl.kt b/src/test/kotlin/org/briarproject/briar/desktop/testdata/DeterministicTestDataCreatorImpl.kt
index af945f60004d099c9e6dbec8b25420f79aadebb9..4e8fa3d744515c94533dbb48c6ea95d278209d8a 100644
--- a/src/test/kotlin/org/briarproject/briar/desktop/testdata/DeterministicTestDataCreatorImpl.kt
+++ b/src/test/kotlin/org/briarproject/briar/desktop/testdata/DeterministicTestDataCreatorImpl.kt
@@ -293,7 +293,7 @@ class DeterministicTestDataCreatorImpl @Inject internal constructor(
         groupId: GroupId,
         message: org.briarproject.briar.desktop.testdata.Message
     ) {
-        val timestamp = message.date.toEpochSecond(ZoneOffset.UTC)
+        val timestamp = message.date.toEpochSecond(ZoneOffset.UTC) * 1000
         val text = message.text
         val local = message.direction == Direction.OUTGOING
         val autoDelete = random.nextBoolean()