diff --git a/src/Mailer.ts b/src/Mailer.ts
index bf844f1..c0cd66e 100644
--- a/src/Mailer.ts
+++ b/src/Mailer.ts
@@ -126,6 +126,7 @@ export class Mailer {
      */
     public async sendWelcomeMail(to_address: string, token: string, locale: string = "en") {
         await i18next.changeLanguage(locale);
+        token = Buffer.from(token).toString("base64");
 
         const replacements = {
             recipient_mail: to_address,
@@ -159,6 +160,7 @@ export class Mailer {
      */
     public async sendSelfserviceForgottenMail(to_address: string, token: string, locale: string = "en") {
         await i18next.changeLanguage(locale);
+        token = Buffer.from(token).toString("base64");
 
         const replacements = {
             recipient_mail: to_address,