diff --git a/core/admin/mailu/internal/views/postfix.py b/core/admin/mailu/internal/views/postfix.py
index 5ff31584..e94bfc28 100644
--- a/core/admin/mailu/internal/views/postfix.py
+++ b/core/admin/mailu/internal/views/postfix.py
@@ -12,13 +12,13 @@ def postfix_mailbox_domain(domain_name):
     return flask.jsonify(domain.name)
 
 
-@internal.route("/postfix/mailbox/<email>")
+@internal.route("/postfix/mailbox/<path:email>")
 def postfix_mailbox_map(email):
     user = models.User.query.get(email) or flask.abort(404)
     return flask.jsonify(user.email)
 
 
-@internal.route("/postfix/alias/<alias>")
+@internal.route("/postfix/alias/<path:alias>")
 def postfix_alias_map(alias):
     localpart, domain_name = models.Email.resolve_domain(alias)
     if localpart is None:
@@ -27,7 +27,7 @@ def postfix_alias_map(alias):
     return flask.jsonify(",".join(destination)) if destination else flask.abort(404)
 
 
-@internal.route("/postfix/transport/<email>")
+@internal.route("/postfix/transport/<path:email>")
 def postfix_transport(email):
     if email == '*':
         return flask.abort(404)
@@ -36,7 +36,7 @@ def postfix_transport(email):
     return flask.jsonify("smtp:[{}]".format(relay.smtp))
 
 
-@internal.route("/postfix/sender/login/<sender>")
+@internal.route("/postfix/sender/login/<path:sender>")
 def postfix_sender_login(sender):
     localpart, domain_name = models.Email.resolve_domain(sender)
     if localpart is None:
@@ -45,7 +45,7 @@ def postfix_sender_login(sender):
     return flask.jsonify(",".join(destination)) if destination else flask.abort(404)
 
 
-@internal.route("/postfix/sender/access/<sender>")
+@internal.route("/postfix/sender/access/<path:sender>")
 def postfix_sender_access(sender):
     """ Simply reject any sender that pretends to be from a local domain
     """
diff --git a/core/admin/mailu/ui/views/admins.py b/core/admin/mailu/ui/views/admins.py
index 7462c545..7daa9d31 100644
--- a/core/admin/mailu/ui/views/admins.py
+++ b/core/admin/mailu/ui/views/admins.py
@@ -33,7 +33,7 @@ def admin_create():
     return flask.render_template('admin/create.html', form=form)
 
 
-@ui.route('/admin/delete/<admin>', methods=['GET', 'POST'])
+@ui.route('/admin/delete/<path:admin>', methods=['GET', 'POST'])
 @access.global_admin
 @access.confirmation_required("delete admin {admin}")
 def admin_delete(admin):
diff --git a/core/admin/mailu/ui/views/aliases.py b/core/admin/mailu/ui/views/aliases.py
index eaab5cad..5e65c86d 100644
--- a/core/admin/mailu/ui/views/aliases.py
+++ b/core/admin/mailu/ui/views/aliases.py
@@ -36,7 +36,7 @@ def alias_create(domain_name):
         domain=domain, form=form)
 
 
-@ui.route('/alias/edit/<alias>', methods=['GET', 'POST'])
+@ui.route('/alias/edit/<path:alias>', methods=['GET', 'POST'])
 @access.domain_admin(models.Alias, 'alias')
 def alias_edit(alias):
     alias = models.Alias.query.get(alias) or flask.abort(404)
@@ -53,7 +53,7 @@ def alias_edit(alias):
         form=form, alias=alias, domain=alias.domain)
 
 
-@ui.route('/alias/delete/<alias>', methods=['GET', 'POST'])
+@ui.route('/alias/delete/<path:alias>', methods=['GET', 'POST'])
 @access.domain_admin(models.Alias, 'alias')
 @access.confirmation_required("delete {alias}")
 def alias_delete(alias):