403 errors on Get Profile endpoint

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We have an integration between our platform (MentionMe) and Klaviyo and we’ve recently been seeing more and more 403 errors when calling the Get Profile endpoint ( Think we saw this first ones on 15 March, and last night we saw about 150 of these for various Klaviyo clients.

I had a look at our logs and the response we’re getting from the API is the one bellow:

[image removed]

These seems to usually happen during the night. For example, last night we had errors between 06/04/2022 02:14:02 - 06/04/2022 04:08:31

I’ve checked the Klaviyo status page but there is no incident reported there.


Has anyone else seen something similar?


Best answer by IainD 13 April 2022, 10:39

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13 replies

Userlevel 7
Badge +58

Hi there@alexoanea,

Welcome to the Community,

A relatively common reason for this is if you have a firewall or other security measures in place that may be rate-limiting or blocking Klaviyo after detecting large transfers of data. The solution to this is to whitelist Klaviyo. As Klaviyo uses dynamic IPs, we do not provide a range of IPs to customers. Instead, we recommend whitelisting our user agent, which is: Klaviyo/1.0

This could also be due to a bad API key, syntax error, or due to be running from javascript. See "group memberships" in the API documentation.


If not, it could be that you're using our server side endpoint for a client side call. If this is the case, I would recommend switching this as I don't think we will allow cross origin requests.
Here is an example ajax call that you should be able to utilize if you're sending from the client side:

var settings = {
  "async": true,
  "crossDomain": true,
  "url": "",
  "method": "POST",
  "headers": {
    "content-type": "application/x-www-form-urlencoded",
    "cache-control": "no-cache"
  "data": {
    "g": “{{LIST_ID}}",
    "$fields": "vote",
    "email": “{{email}}",
    "vote": "vote"

$.ajax(settings).done(function (response) {

Additional info can be found here.



Badge +3

Hi Alex,


Thank you for the reply.

I’m getting the error on the following endpoint:{person_id}

I’m using (( ) for this integration and I’m pretty sure there is no rate limiting on their side as I’ve had projects that dealt with a lot more request/data and if there was ever a rate limiting issue it was always on the API side and not on the client (


I’m also ruling out the bad API key, syntax error, or due to be running from javascript as these integrations have been running OK for months and they keep running OK most of the time but in recent weeks (starting 15th March we’ve seen periods (particularly during night) where request fail this way across all Klaviyo Clients (we have around 40 clients live with this integration).


Is Klaviyo using Cloudflare? could it be an issue with Cloudflare blocking the IP on the Klaviyo side? If so, would it be possible to whitelist on the Klaviyo Cloudflare?


Kind regards,



Userlevel 7
Badge +58

Hi there @alexoanea,

To start, I will say that although we use Cloudflare, I cannot request for one-off IPs to be whitelisted as there is a much more detailed process behind that.

I'm slightly confused what it is that you are trying to do. It sounds like you are using a third party tool to integrate a different software with Klaviyo but when making that v1/person request its being denied/blocked with a 403 aka a server/authentication issue. I think there is something more systematic than Klaviyo's cloudflare blocking these accounts. If you could further explain your goals and how you want the data to interact between Klaviyo, MentionMe, and that could help.

Additional note, the time of day should not be a variable.


All the best,



Badge +3

Hi Alex,

We have a integration between Mention Me and Klaviyo based on the Mention Me webhooks. We send the webhooks to where they get processed and depending on webhook type and payload values we make various calls to the Klaviyo API to create/update profiles, track profile activity, subscribe profiles to lists using the Klaviyo connector 

We’ve been running this integration for about 1 year now and have about 50 clients using it. Only in recent weeks we started seeing these 403 errors which seem Klaviyo’s Cloudflare blocking the requests rather than the Klaviyo API rejecting the calls. I only mentioned the time of day because every time it happened was out of office hours.

This issue occurred for only a small number of requests reported to the total number of requests: 59/27343 on 2rd April and and 128/30382 on 6th April.

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Hi Alex and Alex

I’m experiencing the same problem...

I’m calling the metrics API ( from Google Sheets using AppScript for reporting purposes.

Looking at my error logs, I can see that the problem started suddenly on 29th March. Seven error 403s were reported on that day compared to none in the previous month… Now I get error notifications every day with up to 50% of daily calls failing in some cases (I’m calling the API every 6 hours).

Look forward to your thoughts Alex H…

Thanks, Iain

Userlevel 7
Badge +58

Hi there @IainD,

Just a few questions for you. Are all these calls coming from the same IP address? Do you have any retry logic implemented in your integration to retry requests that fail?


All the best,


Badge +1

Hi @alex.hong 

All fixed now - no errors over the last 2 days having had multiple errors per day over the previous 2 weeks. Please thank your developers ;-)

To answer your questions, though, I think AppScript uses multiple IPs - see

It would be easy to add retry requests but the data is not mission critical so I can afford a few fails per day.

Many thanks


Badge +3

After a long period of no issues this seems to have come back since 21/09/2022 04:55:23 BST. Since around that time all the requests from our integration seem to be blocked by Cloudflare again as we get this as the response. See attached screenshot of response.

This is valid across tens of Klaviyo accounts, each with their out API Authentications. As mentioned before, it seems that Cloudflare is blocking calls from certain IPs  (requests from would come from 1 or 2 IPs only. Any way we can fix this/ prevent it from happening in the future?

Userlevel 7
Badge +60

Hey @alexoanea,

I would suggest trying again to see if those requests were still getting block. 

We recently noticed an incident regarding a partial API outage causing an elevation in 403 errors. You can find more details and subscribe to the public incident report here


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Hi @David To,

Thanks for the update! I had checked the Klaviyo Status page when I saw this started happening and there was nothing yet reported. Guess the incident was reported a bit later. We’ve replayed all the failed requests soon after the outage was resolved.






Hi community! I’m on magento2 with direct api connection. fastly/cloudflare. The 403 errors are still coming up for us seemingly randomly/intermittently and blocking email traffic. Should I create new api keys to clear up the issue?

Userlevel 7
Badge +58

Hi @lsamuels ,

I would try that first and if the problems seem to persist, then contact our Support team to see if there are any errors and the disconnects aren’t just random.

Userlevel 1
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