update

email/base.gohtml

@@ -347,7 +347,22 @@
                       <br />
                       {{ if .Sender }}{{.Sender}}{{else}}{{.App.Name}}{{end}}
                     </p>
-                    
+                    {{ with .Actions }} 
+                      <table class="body-sub">
+                        <tbody>
+                            {{ range $action := . }}
+                              {{if $action.Button.Text}}
+                              <tr>
+                                <td>
+                                  <p class="sub">{{$.App.TroubleText | replace "{ACTION}" $action.Button.Text}}</p>
+                                  <p class="sub"><a href="{{ $action.Button.Link }}">{{ $action.Button.Link }}</a></p>
+                                </td>
+                              </tr>
+                              {{ end }}
+                            {{ end }}
+                        </tbody>
+                      </table>
+                    {{ end }}
                   </td>
                 </tr>
               </table>

email/email.go

@@ -19,6 +19,7 @@ type App struct {
 	Link        string
 	Logo        string
 	Copyright   string
+	TroubleText string
 }
 
 type Button struct {

email/engine.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	_ "embed"
 	"html/template"
+	"strings"
 
 	"github.com/vanng822/go-premailer/premailer"
 	"github.com/yuin/goldmark"
@@ -29,6 +30,9 @@ func init() {
 		"mul": func(a, b int) int {
 			return a * b
 		},
+		"replace": func(from, to, input string) string {
+			return strings.Replace(input, from, to, -1)
+		},
 	}).Parse(mailTmpl))
 }
 

email/service.go

@@ -37,5 +37,6 @@ func setupDefault() {
 		time.Now().Year(), app.Name)
 	app.Link = "https://kumoly.io"
 	app.Logo = "http://www.duchess-france.org/wp-content/uploads/2016/01/gopher.png"
+	app.TroubleText = "If you’re having trouble with the button '{ACTION}', copy and paste the URL below into your web browser."
 	dial = gomail.NewDialer("mail.kumoly.io", 587, "test@kumoly.io", "test")
 }