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“An error occurred when fetching data." but only sometimes



I have a weird error on my react/redux web app. It’s happening only sometimes and never to me but only to my customer. I can’t reproduce it and if my customer reload the page it’s working.

I can track the error because i listen for this event :

lock.on('unrecoverable_error', (unrecoverable_error) => {
	console.log('unrecoverable_error:  ', unrecoverable_error)

And with logException i send the error to Sentry. And Sentry give me this error :

unrecoverable_error:   Error: An error occurred when fetching data.

It’s happening when they click on a button to open the lock (on click i dispatch an action who
The lock is not showed. After reload it’s working. It seems that the lock Auth0Lock is not correctly load.
But why only sometimes ?

Can someone at Auth0 look into this ? I can share my private repo so you can take a look. and i can share my website url so you can test yourself.
I know it’s difficult to fix a bug when their is not step for reproduction…

Thanks for the help. I’m loosing customer and i can’t find how to fix this…


Can you please share your website URL for me to investigate. If you prefer to do this privately, please let me know.


I prefer to share it privately. (it’s still in beta and not really public!)
How can i do that ?


I have created a ticket for you in our support system. Please provide the additional info in that ticket.


This error is thrown when Lock can’t fetch the client/tenant settings or the language file due to timeout, or other network issues. We have improved the handling of this error to show error messages in Lock, and increasing the timeout - these have been implemented in Lock v10.15.0 onwards.

If you are experiencing this issue using a lower version of Lock, please upgrade to v10.15.0 or greater.


And the related Github issue :


Hi Prashant,

I am getting this same issue. I am proxying through Gatling to perform some load testing for a web app my company have built and the authentication is done by Auth0 of course, I then get this error. Is it something to do with how our website is getting its SSL cert’s when hitting auth0 via Gatling?

Any help would be appreciated.