diff --git a/src/cli/templates/base-config.yaml b/src/cli/templates/base-config.yaml
index ef6d21fe..198094a7 100644
--- a/src/cli/templates/base-config.yaml
+++ b/src/cli/templates/base-config.yaml
@@ -60,7 +60,7 @@ services:
     project: {{ services.redmine_mailbox.project | default('', true) }}
     redmine_update_time: {{ services.redmine_mailbox.redmine_update_time | default(10, true) }}
     answer_tag: {{ services.redmine_mailbox.answer_tag | default('-- archi -- Resolving email was sent', true) }}
-    imap4_port: {{ services.redmine_mailbox.imap4_port | default(143, true) }}
+    imap4_port: {{ services.redmine_mailbox.imap4_port | default(993, true) }}
     mailbox_update_time: {{ services.redmine_mailbox.mailbox_update_time | default(10, true) }}
   postgres:
     port: {{ services.postgres.port | default(5432, true) }}
diff --git a/src/interfaces/redmine_mailer_integration/mailbox.py b/src/interfaces/redmine_mailer_integration/mailbox.py
index 646538a1..86cdfa29 100644
--- a/src/interfaces/redmine_mailer_integration/mailbox.py
+++ b/src/interfaces/redmine_mailer_integration/mailbox.py
@@ -227,7 +227,7 @@ def _connect(self):
         Open the mailbox
         """
         logger.info(f"Open mailbox (U:{self.user} P:*********)")
-        mailbox = imaplib.IMAP4(host='ppc.mit.edu', port=self.config["imap4_port"], timeout=None)
+        mailbox = imaplib.IMAP4_SSL(host='ppc.mit.edu', port=self.config["imap4_port"], timeout=None)
         mailbox.login(self.user, self.password)
 
         return mailbox