diff --git a/test/config/dovecot.cf b/test/config/dovecot.cf
index 35279f28..47e76619 100644
--- a/test/config/dovecot.cf
+++ b/test/config/dovecot.cf
@@ -1 +1,2 @@
 mail_max_userip_connections = 69
+recipient_delimiter = ~
diff --git a/test/config/postfix-main.cf b/test/config/postfix-main.cf
index 37155392..e5f3d0fe 100644
--- a/test/config/postfix-main.cf
+++ b/test/config/postfix-main.cf
@@ -1,2 +1,3 @@
+recipient_delimiter = ~
 max_idle = 600s
 readme_directory = /tmp
diff --git a/test/email-templates/existing-alias-recipient-delimiter.txt b/test/email-templates/existing-alias-recipient-delimiter.txt
index ef5b9a4a..39052986 100644
--- a/test/email-templates/existing-alias-recipient-delimiter.txt
+++ b/test/email-templates/existing-alias-recipient-delimiter.txt
@@ -1,6 +1,6 @@
 HELO mail.external.tld
 MAIL FROM: user@external.tld
-RCPT TO: alias1+test@localhost.localdomain
+RCPT TO: alias1~test@localhost.localdomain
 DATA
 From: Docker Mail Server <dockermailserver@external.tld>
 To: Existing Local Alias With Delimiter <alias1+test@localhost.localdomain>
diff --git a/test/tests.bats b/test/tests.bats
index f8769e5b..66a7bd3b 100644
--- a/test/tests.bats
+++ b/test/tests.bats
@@ -273,9 +273,12 @@ load 'test_helper/bats-assert/load'
 }
 
 @test "checking smtp: delivers mail to existing alias with recipient delimiter" {
-  run docker exec mail /bin/sh -c "grep 'to=<user1+test@localhost.localdomain>, orig_to=<alias1+test@localhost.localdomain>' /var/log/mail/mail.log | grep 'status=sent' | wc -l"
+  run docker exec mail /bin/sh -c "grep 'to=<user1~test@localhost.localdomain>, orig_to=<alias1~test@localhost.localdomain>' /var/log/mail/mail.log | grep 'status=sent' | wc -l"
   assert_success
   assert_output 1
+
+  run docker exec mail /bin/sh -c "grep 'to=<user1~test@localhost.localdomain>' /var/log/mail/mail.log | grep 'status=bounced'"
+  assert_failure
 }
 
 @test "checking smtp: delivers mail to existing catchall" {