diff --git a/jmclient/jmclient/payjoin.py b/jmclient/jmclient/payjoin.py
index 32c2ee9..b7c91a0 100644
--- a/jmclient/jmclient/payjoin.py
+++ b/jmclient/jmclient/payjoin.py
@@ -457,7 +457,7 @@ def send_payjoin(manager, accept_callback=None,
     # which tls certificate verification is ignored.
     tls_whitelist = None
     if isinstance(jm_single().bc_interface, RegtestBitcoinCoreInterface):
-        tls_whitelist = ["127.0.0.1"]
+        tls_whitelist = [b"127.0.0.1"]
 
     manager.set_payment_tx_and_psbt(payment_psbt)