diff --git a/protocols/luci-proto-mbim/htdocs/luci-static/resources/protocol/mbim.js b/protocols/luci-proto-mbim/htdocs/luci-static/resources/protocol/mbim.js
index 82472a3459..9791f44328 100644
--- a/protocols/luci-proto-mbim/htdocs/luci-static/resources/protocol/mbim.js
+++ b/protocols/luci-proto-mbim/htdocs/luci-static/resources/protocol/mbim.js
@@ -64,6 +64,7 @@ return network.registerProtocol('mbim', {
 
 		o = s.taboption('general', form.Value, 'apn', _('APN'));
 		o.validate = function(section_id, value) {
+			if (value == null || value == '') return true;
 			if (!/^[a-zA-Z0-9\-.]*[a-zA-Z0-9]$/.test(value))
 				return _('Invalid APN provided');