diff --git a/README.md b/README.md
index 7bff8b3f..1ed34141 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,8 @@ An action that simply sends a mail to multiple recipients.
     cc: kyloren@example.com,leia@example.com
     # Optional blind carbon copy recipients
     bcc: r2d2@example.com,hansolo@example.com
+    # Optional unsigned/invalid certificates allowance:
+    ignore_cert: true
     # Optional content type (defaults to text/plain):
     content_type: text/html
     # Optional converting Markdown to HTML (set content_type to text/html too):
diff --git a/action.yml b/action.yml
index 6a316dd6..ce142980 100644
--- a/action.yml
+++ b/action.yml
@@ -35,6 +35,9 @@ inputs:
   bcc:
     description: Blind carbon copy recipients (separated with comma)
     required: false
+  ignore_cert:
+    description: Allow unsigned/invalid certificates
+    required: false
   content_type:
     description: Content-Type HTTP header (text/html or text/plain)
     required: false
diff --git a/main.js b/main.js
index feadfce5..d36b8077 100644
--- a/main.js
+++ b/main.js
@@ -44,6 +44,7 @@ async function main() {
         const contentType = core.getInput("content_type", { required: true })
         const attachments = core.getInput("attachments", { required: false })
         const convertMarkdown = core.getInput("convert_markdown", { required: false })
+        const ignoreCert = core.getInput("ignore_cert", { required: false })
 
         const transport = nodemailer.createTransport({
             host: serverAddress,
@@ -53,6 +54,9 @@ async function main() {
                 user: username,
                 pass: password,
             }
+            tls: ignoreCert ? {
+                rejectUnauthorized: false
+            } : undefined
         })
 
         const info = await transport.sendMail({