diff --git a/addons/mail/i18n/mail.pot b/addons/mail/i18n/mail.pot
index a2f6a8a923c..3b802987106 100644
--- a/addons/mail/i18n/mail.pot
+++ b/addons/mail/i18n/mail.pot
@@ -2219,7 +2219,7 @@ msgstr ""
 msgid "Policy to post a message on the document using the mailgateway.\n"
 "- everyone: everyone can post\n"
 "- partners: only authenticated partners\n"
-"- followers: only followers of the related document or members of following channels that are not public\n"
+"- followers: only followers of the related document or members of following channels\n"
 ""
 msgstr ""
 
diff --git a/addons/mail/models/mail_alias.py b/addons/mail/models/mail_alias.py
index 0c251fec93a..ba1afd02d45 100644
--- a/addons/mail/models/mail_alias.py
+++ b/addons/mail/models/mail_alias.py
@@ -78,7 +78,7 @@ class Alias(models.Model):
         help="Policy to post a message on the document using the mailgateway.\n"
              "- everyone: everyone can post\n"
              "- partners: only authenticated partners\n"
-             "- followers: only followers of the related document or members of following channels that are not public\n")
+             "- followers: only followers of the related document or members of following channels\n")
 
     _sql_constraints = [
         ('alias_unique', 'UNIQUE(alias_name)', 'Unfortunately this email alias is already used, please choose a unique one')
diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index 81a335e4dee..f97978b47b0 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -870,7 +870,7 @@ class MailThread(models.AbstractModel):
                 obj = self.env[alias.alias_parent_model_id.model].browse(alias.alias_parent_thread_id)
             accepted_partner_ids = list(
                 set(partner.id for partner in obj.message_partner_ids) |
-                set(partner.id for channel in obj.message_channel_ids if channel.public != 'public' for partner in channel.channel_partner_ids)
+                set(partner.id for channel in obj.message_channel_ids for partner in channel.channel_partner_ids)
             )
             if not author_id or author_id not in accepted_partner_ids:
                 _warn('alias %s restricted to internal followers, skipping' % alias.alias_name)