diff --git a/unipay/providers/transfer.py b/unipay/providers/transfer.py
index 8165f2b..069d5f6 100644
--- a/unipay/providers/transfer.py
+++ b/unipay/providers/transfer.py
@@ -145,6 +145,7 @@ class TransferGateway(Gateway):
 		from ahserver.serverenv import ServerEnv
 		self.running = True
 		while self.running:
+			debug(f'mail check loop running')
 			try:
 				ec = EmailClient(self.pop3server, self.email, self.password)
 				count, _ = ec.stat()
@@ -155,11 +156,14 @@ class TransferGateway(Gateway):
 					try:
 						mail = ec.get_mail(i)
 						if mail.mailfrom != '95555@message.cmbchina.com':
+							debug(f'ignored mail from {mail.mailfrom=}')
 							continue
 						if not mail.body.startswith('动账业务通知'):
+							debug(f'ignored mail from {mail.mailfrom=} not start with 动账业务通知{mail.body=}')
 							continue
 						data = self.get_transfer_data(mail)
 						if data is None:
+							debug(f'ignored mail from {mail.mailfrom=} get data error {mail.body=}')
 							continue
 						debug(f'transfer mail matched: code={data.code}, amount={data.amount}')