Upstream Connect Error or Disconnect/Reset: Meaning?

Here’s what “upstream connect error or disconnect/reset before headers connection failure” means and how to fix it:

If you are an everyday user, and you see this message while browsing the internet, then it simply means that you need to clear your cache and cookies.

If you are a developer and see this message, then you need to check your service routes, destination rules, and/or traffic management with applications.

So if you want to learn all about what this 503 error means exactly and how to fix it, then this article is for you.

Let’s delve deeper into it!

Upstream Connect Error or Disconnect/Reset: Meaning? (Fix)

What Does Upstream Connect Error or Disconnect/Reset Before Headers Connection Failure Mean?

Upstream connect error or disconnect reset before headers reset reason connection failure.

That’s a very specific, yet unclear error message to see.

What is it trying to tell you?

Let’s start with an overview.

This is a 503 error message.

It’s a generic message that actually applies to a lot of different scenarios, and the fix for it will depend on the specific scenario at hand.

In general, this error is telling you that there is a connection error, and that error is linked to routing services and rules. 

That leaves an absolute ton of possibilities, but I’ll take you through the most common sources.

Then, we can talk about troubleshooting and fixing the problem.

What Causes Upstream Connect Error or Disconnect/Reset Before Headers Connection Failure? (3 Things)

That covers the very zoomed-out picture of this error message, but if you’re getting it, then you probably want to get it to go away.

To fix the problem, we have to address the root cause.

That’s the essence of troubleshooting, and it definitely applies here.

There’s a problem when it comes to identifying the cause of this error.

There are basically two instances where you’re going to see this error, and they are completely different.

One place where you’ll run into it is when you’re coding specific functions that relate to network connection management.

I’m going to break down the three most common scenarios that lead to this error in the next few sections.

But, the other common time you see this error is when you’re browsing the internet.

That means that I’m really answering this question for two very different groups of people.

One group is developing or coding networking resources.

The other group is just browsing the internet.

As you might imagine, it’s hard to consolidate all of that into a single, concise answer.

So, I’m going to split this up.

First, I’ll tackle the developer problems.

If you’re just trying to browse the internet and don’t want to get deep into networking and how it works, then skip to the section that is clearly labeled as not for developers and programmers.

That said, if you want to take a peek behind the curtain and learn a little more about networking, I’ll try to keep these explanations as light as possible.

#1 Reconfiguring Service Routes

I mentioned before that this is a 503 error.

One common place you’ll find it is when reconfiguring service routes.

The boiled-down essence here is that it’s easy to mix up service routing and rules such that the system can receive subsets before they are designed.

Naturally, the system doesn’t know what to do in that case, and you get a 503 error.

The key to avoiding this problem with service route reconfiguring is to follow what you might call a “make-before-break” rule.

Essentially, the steps force the system to add the new subset first and then update the virtual services.

#2 Setting Destination Rules

Considering the issue above, it should not come as a surprise that you can trigger 503 errors when setting destination rules.

Most commonly, destination rules are the issue if you see the 503 errors right after a request to a service. 

This issue goes hand in hand with the one above.

The problem is still that the destination rule is creating the issue.

The difference is that this isn’t necessarily a problem with receiving subsets before they have been designed.

Virtually any destination rule error can lead to a 503 message.

Since there are so many ways these rules can break down and so many ways the problems can manifest, I’m going to cheat a little.

If you noticed that the problem correlates with new destination rules, then you can follow this guide.

It breaks down the most common destination rule problems and shows you how to overcome them.

#2 Traffic Management With Applications

The third primary issue is related to conflicts between applications and any proxy sidecar.

In other words, the applications that work with your traffic management rules might not know those rules, and the application can do things that don’t play well with the traffic management system.

That’s pretty vague because, once again, there are a lot of specific possibilities.

The gist is that you’re trying to offload as much error recovery to the applications as you can.

That will minimize these conflicts and resolve most instances of 503 errors.

How Do You Fix Upstream Connect Error or Disconnect/Reset Before Headers Connection Failure?

Considering the detailed problems we just covered, what can you do about the 503 error?

I included some solutions and linked to even more, but if you’re looking for a general guide, then here’s another way to think about the whole thing.

This specific message is telling you that there’s a timing problem between connect errors and disconnect resets.

Somewhere in your system, you have conflicting rules that are trying to do things out of order.

The best way to find the specific area is to focus on rules changes as they relate to traffic management.

Essentially, start with what you touched most recently, and work your way backward from there.

Ok, But What If I’m not a Developer or Programmer? (3 Steps)

Alright. That was a relatively deep walk-through connection rules development.

If you’re still with me, that’s great.

We’re going to switch gears and look at this from a simple user perspective.

You don’t need to know any coding to run into this problem, and I’m going to show you how to solve it without any coding either.

It’s actually pretty simple.

#1 The Walmart Bug

But, it still makes more sense when you know more about what went wrong.

So, I’m going to cite one of the most prolific examples of everyday 503 errors.

In 2020, Walmart’s website ran into widespread issues.

Users could browse the site just fine, but when they tried to go to a specific product page to make a purchase, they got the 503 error.

It popped up word for word as I mentioned it before: Upstream connect error or disconnect reset before headers reset reason connection failure.

People were just trying to buy some stuff, and they got hit with this crazy message.

What are you supposed to do with it?

#2 An Easy Fix

Well, the message is actually giving you very specific advice, once you know how to read it.

It’s telling you that your computer and the Walmart servers had a connection failure, and when they tried to automatically fix that connection problem, things broke down.

A quick note: I’m using the famous Walmart bug as an example, but the problems and solutions discussed here will work any time you see this message while browsing the web.

What that means is that there is some piece of information that is tied to your connection to the Walmart site that is messing up the automatic reconnect protocols.

While that might sound a little vague and mysterious, it actually tells us exactly where the problem lies.

The only information that could exist in this space would have to be stored in your browser’s cache.

This is related to your cookies.

Basically, when the error first went wrong, your computer remembered the problem, and so it just kept doing things the wrong way over and over again.

The solution requires you to make your computer forget the bad rule that it’s following.

To do that, you simply need to clear your cache and cookies.

#3 Clearing the Cache

The famous Walmart problem-plagued Chrome users, so I’ll walk you through how to do this on Google Chrome.

If you use a different browser, you can just look up how to clear cache and cookies.

Before we go through the steps, let me explain what is going to happen here.

We’re not deleting anything that is particularly important.

Your internet cache is just storing information related to the websites you visit.

Then, if you go back to that website or reload it, the stored information means that your computer doesn’t actually have to download as much information, and everything can load a little faster and easier.

So, when you delete this cache, it’s going to do a few things.

It’s going to slow down your first visit to any site that no longer has cached files.

But after you visit a site, it will build new cache files, and things will work normally.

This is also going to make your computer forget your sign-in information for any sites that require such.

Sticking with Walmart as an example, if you were signed into the website with your account, then after you clear the cache, you’re going to be automatically signed out again.

Make sure you know your passwords and usernames.

Because of this last issue, some people don’t like to clear their cache.

If you’re worried about that, then you don’t have to clear everything.

Just clear the cache back through the day when the error started.

Ok. With all of that covered, let’s go through the steps: 

  1. Look for the three dots and click on them (this opens the tools menu).
  2. Choose “history” from the list.
  3. Choose the time frame on the right that covers the data you want to clear.
  4. Click on “Clear browsing data.”
  5. Look at the checkboxes. You can choose cookies, cached images and files, and browsing history.
  6. To be sure you resolve the 503 error, clear the cookies and cached files.
  7. Click on “Clear Data” and you’re done.