diff --git a/src/ozonetel/ozonetel-admin-auth.service.ts b/src/ozonetel/ozonetel-admin-auth.service.ts
index d3c70ca..c7d1f60 100644
--- a/src/ozonetel/ozonetel-admin-auth.service.ts
+++ b/src/ozonetel/ozonetel-admin-auth.service.ts
@@ -54,10 +54,14 @@ export class OzonetelAdminAuthService implements OnModuleInit {
         return this.login();
     }
 
-    private rsaEncrypt(publicKeyPem: string, plaintext: string): string {
+    private rsaEncrypt(publicKeyRaw: string, plaintext: string): string {
+        // Ozonetel returns raw base64 without PEM headers — wrap it
+        const pem = publicKeyRaw.includes('-----BEGIN')
+            ? publicKeyRaw
+            : `-----BEGIN PUBLIC KEY-----\n${publicKeyRaw}\n-----END PUBLIC KEY-----`;
         const buffer = Buffer.from(plaintext, 'utf8');
         const encrypted = publicEncrypt(
-            { key: publicKeyPem, padding: cryptoConstants.RSA_PKCS1_PADDING },
+            { key: pem, padding: cryptoConstants.RSA_PKCS1_PADDING },
             buffer,
         );
         return encrypted.toString('base64');