diff --git a/pkgs/build-support/node/fetch-npm-deps/src/util.rs b/pkgs/build-support/node/fetch-npm-deps/src/util.rs
index 023ba56793b90..36e2333a3e1a8 100644
--- a/pkgs/build-support/node/fetch-npm-deps/src/util.rs
+++ b/pkgs/build-support/node/fetch-npm-deps/src/util.rs
@@ -1,3 +1,4 @@
+use anyhow::bail;
 use backoff::{retry, ExponentialBackoff};
 use data_encoding::BASE64;
 use digest::Digest;
@@ -5,6 +6,7 @@ use isahc::{
     config::{CaCertificate, Configurable, RedirectPolicy, SslOption},
     Body, Request, RequestExt,
 };
+use log::info;
 use nix_nar::{Encoder, NarError};
 use serde_json::{Map, Value};
 use sha2::Sha256;
@@ -15,7 +17,7 @@ use std::{
 };
 use url::Url;
 
-pub fn get_url(url: &Url) -> Result<Body, isahc::Error> {
+pub fn get_url(url: &Url) -> Result<Body, anyhow::Error> {
     let mut request = Request::get(url.as_str()).redirect_policy(RedirectPolicy::Limit(10));
 
     // Respect SSL_CERT_FILE if environment variable exists
@@ -37,16 +39,27 @@ pub fn get_url(url: &Url) -> Result<Body, isahc::Error> {
         if let Ok(npm_tokens) = env::var("NIX_NPM_TOKENS") {
             if let Ok(tokens) = serde_json::from_str::<Map<String, Value>>(&npm_tokens) {
                 if let Some(token) = tokens.get(host).and_then(serde_json::Value::as_str) {
+                    info!("Found NPM token for {}. Adding authorization header to request.", host);
                     request = request.header("Authorization", format!("Bearer {token}"));
                 }
             }
         }
     }
 
-    Ok(request.body(())?.send()?.into_body())
+    let res = request.body(())?.send()?;
+    if !res.status().is_success() {
+        if res.status().is_client_error() {
+            bail!("Client error: {}", res.status());
+        }
+        if res.status().is_server_error() {
+            bail!("Server error: {}", res.status());
+        }
+        bail!("{}", res.status());
+    }
+    Ok(res.into_body())
 }
 
-pub fn get_url_body_with_retry(url: &Url) -> Result<Vec<u8>, isahc::Error> {
+pub fn get_url_body_with_retry(url: &Url) -> Result<Vec<u8>, anyhow::Error> {
     retry(ExponentialBackoff::default(), || {
         get_url(url)
             .and_then(|mut body| {
@@ -56,12 +69,15 @@ pub fn get_url_body_with_retry(url: &Url) -> Result<Vec<u8>, isahc::Error> {
 
                 Ok(buf)
             })
-            .map_err(|err| {
-                if err.is_network() || err.is_timeout() {
-                    backoff::Error::transient(err)
-                } else {
-                    backoff::Error::permanent(err)
+            .map_err(|err| match err.downcast_ref::<isahc::Error>() {
+                Some(isahc_err) => {
+                    if isahc_err.is_network() || isahc_err.is_timeout() {
+                        backoff::Error::transient(err)
+                    } else {
+                        backoff::Error::permanent(err)
+                    }
                 }
+                None => backoff::Error::permanent(err),
             })
     })
     .map_err(|backoff_err| match backoff_err {