diff --git a/proxy/src/auth.rs b/proxy/src/auth.rs
index c8028d1bf0..8c44823c98 100644
--- a/proxy/src/auth.rs
+++ b/proxy/src/auth.rs
@@ -21,7 +21,7 @@ use crate::{
     console,
     error::{ReportableError, UserFacingError},
 };
-use std::io;
+use std::{io, net::IpAddr};
 use thiserror::Error;
 
 /// Convenience wrapper for the authentication error.
@@ -62,10 +62,11 @@ pub enum AuthErrorImpl {
     Io(#[from] io::Error),
 
     #[error(
-        "This IP address is not allowed to connect to this endpoint. \
-        Please add it to the allowed list in the Neon console."
+        "This IP address {0} is not allowed to connect to this endpoint. \
+        Please add it to the allowed list in the Neon console. \
+        Make sure to check for IPv4 or IPv6 addresses."
     )]
-    IpAddressNotAllowed,
+    IpAddressNotAllowed(IpAddr),
 
     #[error("Too many connections to this endpoint. Please try again later.")]
     TooManyConnections,
@@ -87,8 +88,8 @@ impl AuthError {
         AuthErrorImpl::AuthFailed(user.into()).into()
     }
 
-    pub fn ip_address_not_allowed() -> Self {
-        AuthErrorImpl::IpAddressNotAllowed.into()
+    pub fn ip_address_not_allowed(ip: IpAddr) -> Self {
+        AuthErrorImpl::IpAddressNotAllowed(ip).into()
     }
 
     pub fn too_many_connections() -> Self {
@@ -122,7 +123,7 @@ impl UserFacingError for AuthError {
             MalformedPassword(_) => self.to_string(),
             MissingEndpointName => self.to_string(),
             Io(_) => "Internal error".to_string(),
-            IpAddressNotAllowed => self.to_string(),
+            IpAddressNotAllowed(_) => self.to_string(),
             TooManyConnections => self.to_string(),
             UserTimeout(_) => self.to_string(),
         }
@@ -141,7 +142,7 @@ impl ReportableError for AuthError {
             MalformedPassword(_) => crate::error::ErrorKind::User,
             MissingEndpointName => crate::error::ErrorKind::User,
             Io(_) => crate::error::ErrorKind::ClientDisconnect,
-            IpAddressNotAllowed => crate::error::ErrorKind::User,
+            IpAddressNotAllowed(_) => crate::error::ErrorKind::User,
             TooManyConnections => crate::error::ErrorKind::RateLimit,
             UserTimeout(_) => crate::error::ErrorKind::User,
         }
diff --git a/proxy/src/auth/backend.rs b/proxy/src/auth/backend.rs
index 47c1dc4e92..5cb8074cd5 100644
--- a/proxy/src/auth/backend.rs
+++ b/proxy/src/auth/backend.rs
@@ -209,7 +209,7 @@ async fn auth_quirks(
 
     // check allowed list
     if !check_peer_addr_is_in_list(&ctx.peer_addr, &allowed_ips) {
-        return Err(auth::AuthError::ip_address_not_allowed());
+        return Err(auth::AuthError::ip_address_not_allowed(ctx.peer_addr));
     }
     let cached_secret = match maybe_secret {
         Some(secret) => secret,
diff --git a/proxy/src/serverless/backend.rs b/proxy/src/serverless/backend.rs
index 6f93f86d5f..2e63ad6c99 100644
--- a/proxy/src/serverless/backend.rs
+++ b/proxy/src/serverless/backend.rs
@@ -32,7 +32,7 @@ impl PoolingBackend {
         let backend = self.config.auth_backend.as_ref().map(|_| user_info.clone());
         let (allowed_ips, maybe_secret) = backend.get_allowed_ips_and_secret(ctx).await?;
         if !check_peer_addr_is_in_list(&ctx.peer_addr, &allowed_ips) {
-            return Err(AuthError::ip_address_not_allowed());
+            return Err(AuthError::ip_address_not_allowed(ctx.peer_addr));
         }
         let cached_secret = match maybe_secret {
             Some(secret) => secret,
diff --git a/test_runner/regress/test_proxy_allowed_ips.py b/test_runner/regress/test_proxy_allowed_ips.py
index f533579811..7a804114ba 100644
--- a/test_runner/regress/test_proxy_allowed_ips.py
+++ b/test_runner/regress/test_proxy_allowed_ips.py
@@ -24,7 +24,7 @@ async def test_proxy_psql_allowed_ips(static_proxy: NeonProxy, vanilla_pg: Vanil
         with pytest.raises(psycopg2.Error) as exprinfo:
             static_proxy.safe_psql(**kwargs)
         text = str(exprinfo.value).strip()
-        assert "This IP address is not allowed to connect" in text
+        assert "not allowed to connect" in text
 
     # no SNI, deprecated `options=project` syntax (before we had several endpoint in project)
     check_cannot_connect(query="select 1", sslsni=0, options="project=private-project")