diff --git a/src/cert/acme2.js b/src/cert/acme2.js
index 1e55aef65..0da4c2e13 100644
--- a/src/cert/acme2.js
+++ b/src/cert/acme2.js
@@ -139,7 +139,7 @@ Acme2.prototype.updateContact = function (registrationUri, callback) {
     const that = this;
     this.sendSignedRequest(registrationUri, JSON.stringify(payload), function (error, result) {
         if (error) return callback(error);
-        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to update contact. Expecting 200, got %s %s', result.statusCode, result.text)));
+        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to update contact. Expecting 200, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
         debug(`updateContact: contact of user updated to ${that.email}`);
 
@@ -160,7 +160,7 @@ Acme2.prototype.registerUser = function (callback) {
     this.sendSignedRequest(this.directory.newAccount, JSON.stringify(payload), function (error, result) {
         if (error) return callback(error);
         // 200 if already exists. 201 for new accounts
-        if (result.statusCode !== 200 && result.statusCode !== 201) return callback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to register new account. Expecting 200 or 201, got %s %s', result.statusCode, result.text)));
+        if (result.statusCode !== 200 && result.statusCode !== 201) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to register new account. Expecting 200 or 201, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
         debug(`registerUser: user registered keyid: ${result.headers.location}`);
 
@@ -186,7 +186,7 @@ Acme2.prototype.newOrder = function (domain, callback) {
     this.sendSignedRequest(this.directory.newOrder, JSON.stringify(payload), function (error, result) {
         if (error) return callback(error);
         if (result.statusCode === 403) return callback(new BoxError(BoxError.ACCESS_DENIED, `Forbidden sending new order: ${result.body.detail}`));
-        if (result.statusCode !== 201) return callback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to send new order. Expecting 201, got %s %s', result.statusCode, result.text)));
+        if (result.statusCode !== 201) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to send new order. Expecting 201, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
         debug('newOrder: created order %s %j', domain, result.body);
 
@@ -259,7 +259,7 @@ Acme2.prototype.notifyChallengeReady = function (challenge, callback) {
 
     this.sendSignedRequest(challenge.url, JSON.stringify(payload), function (error, result) {
         if (error) return callback(error);
-        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to notify challenge. Expecting 200, got %s %s', result.statusCode, result.text)));
+        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to notify challenge. Expecting 200, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
         callback();
     });
@@ -313,7 +313,7 @@ Acme2.prototype.signCertificate = function (domain, finalizationUrl, csrDer, cal
     this.sendSignedRequest(finalizationUrl, JSON.stringify(payload), function (error, result) {
         if (error) return callback(error);
         // 429 means we reached the cert limit for this domain
-        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to sign certificate. Expecting 200, got %s %s', result.statusCode, result.text)));
+        if (result.statusCode !== 200) return callback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to sign certificate. Expecting 200, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
         return callback(null);
     });
@@ -362,7 +362,7 @@ Acme2.prototype.downloadCertificate = function (hostname, certUrl, callback) {
         that.postAsGet(certUrl, function (error, result) {
             if (error) return retryCallback(new BoxError(BoxError.NETWORK_ERROR, `Network error when downloading certificate: ${error.message}`));
             if (result.statusCode === 202) return retryCallback(new BoxError(BoxError.TRY_AGAIN, 'Retry downloading certificate'));
-            if (result.statusCode !== 200) return retryCallback(new BoxError(BoxError.EXTERNAL_ERROR, util.format('Failed to get cert. Expecting 200, got %s %s', result.statusCode, result.text)));
+            if (result.statusCode !== 200) return retryCallback(new BoxError(BoxError.EXTERNAL_ERROR, `Failed to get cert. Expecting 200, got ${result.statusCode} ${JSON.stringify(result.body)}`));
 
             const fullChainPem = result.body; // buffer