diff --git a/src/lhisp-oauth-client.ts b/src/lhisp-oauth-client.ts
index a8920e1..f18231b 100644
--- a/src/lhisp-oauth-client.ts
+++ b/src/lhisp-oauth-client.ts
@@ -36,7 +36,7 @@ export class LhispOauthClient<iAccessToken extends AccessToken = AccessToken> {
   constructor(params: LhispOauthClientConstructorParams) {
     if (params.certificado) {
       this.agent = new https.Agent({
-        pfx: params.certificado,
+        pfx: Buffer.isBuffer(params.certificado) ? params.certificado : Buffer.from(params.certificado, "base64"),
         passphrase: params.senhaCertificado,
         rejectUnauthorized: false,
       });