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Launch & Analytics: Failed to execute  "Send beacon" - Cannot read property \'toLowerCase\'


Level 2

Hi everyone,


I am now working on implementing new tracking requirement on one site via Launch.


Our rule is triggered by custom event and sent as 

However, it shows the error message in console - Failed to execute  "Send beacon". (see below)

Annotation on 2021-03-16 at 15-19-26.png

I have searched several previous discussion. 

--> some say it can be caused by not updated AA extension--> it is updated.
--> some say it can be caused by not updated Experience Cloud ID extension-->it's updated.


At the same time, the rule "Migrated from DTM: Adobe Analytics - Send Beacon on every page" is fired and sent the beacon without the same error message.


But the tricky thing is that I saw no network request, either.



I am thinking whether it is caused by an outdated plugin? We are still using the same setting that we did several years ago (from DTM period). 



It would be great if someone can give me some hints/direction to troubleshoot.


Many thanks, 



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1 Accepted Solution


Correct answer by
Level 2

The problem is solved. It is caused by the outdated plugin in AA extension in Launch. After we remove the plugin, the network request is sent.

0 Replies


Community Advisor

@wan-yul74421350 - It sounds to me like you have an undefined variable attempting to use .toLowerCase(). If you click on the line number link ("VM4180:81" in your image), it should take you to where the offending code is. You should be able to use this to track back to the code that's causing the problem. With luck, the fix is as easy as adding or updating a data element. Assuming the site is public, if you want to share a link to where we can see the issue, I'd be happy to take a quick look in order to provide better guidance. (Feel free to DM a link, if you want.)


Level 2

Hi Brian, thanks for the reply.

Unfortunately, it is on our staging environment and only accessible via internal network.
I clicked "VM..." and it brings me here (see below): 

Annotation on 2021-03-17 at 09-39-48.png

Besides, I tried to search where the "toLowerCase" is used. 



I also thought whether it is caused that I clicked or not-clicked the "force lowercase value" when setting data element in Launch. 

(The data elements are js variables, that come from the event payloads.)

But no matter it is clicked or not, the same error occurs. 



Is the issue caused by the site side? (i.e. our custom event setting?)


Many thanks and best regards, 



Community Advisor
Unfortunately, it's hard to pinpoint this sort of issue without being able to see the code in action. With the little I know about your implementation, I would suggest trying a couple of things: 1) Based on the image you shared, try making sure you have at least something in s.linkInternalFilters in the Adobe Analytics extension setup and 2) Make sure that all of your data layer properties that are referenced in the rule you're having trouble with have a value. If either of these fixes the issue, work backwards by removing the changes one at a time until you isolate the issue. That should give you ideas on how to implement a fix.


Correct answer by
Level 2

The problem is solved. It is caused by the outdated plugin in AA extension in Launch. After we remove the plugin, the network request is sent.