To mention I am using Appwrite 1.5.5 and SDK version is 12.0.4. Also when I trying to send SMS from localhost, it is giving me the same XMLHTTP error when using "https" on end point but is working fine on "http" end point. Similar things is happening on live website, it's working for "https" and not "http". I have used client.setSelfSigned(status: true) as well.