# Trying to do RUM injection but receiving an odd response from the 'rb' POST

**URL:** <https://community.dynatrace.com/t/trying-to-do-rum-injection-but-receiving-an-odd-response-from-the-rb-post/20461>\
**Category:** Real User Monitoring\
**Tags:** real-user-monitoring-classic, user-sessions\
**Created:** [April 26, 2019, 10:26am UTC](https://community.dynatrace.com/t/trying-to-do-rum-injection-but-receiving-an-odd-response-from-the-rb-post/20461 "2019-04-26T10:26:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![matthew\_eiseng1](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/matthew_eiseng1/32/10897_2.png) [@matthew\_eiseng1](https://community.dynatrace.com/u/matthew_eiseng1)\
**Post date:** [April 26, 2019, 10:26am UTC](https://community.dynatrace.com/t/trying-to-do-rum-injection-but-receiving-an-odd-response-from-the-rb-post/20461/1 "2019-04-26T10:26:42Z")

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Hi,

I’m currently trying to do RUM injection and am running into an issue when using AWS WAF and CloudFront.

The ruxitagentjs is auto-injecting from the web server correctly and trying to POST. On the confirmation of the POST from the web browser to the web server, instead of seeing the ‘200 OK’ or ‘200 apache’ message we see ‘FL(apache,NoCookies)’.

I can only assume the WAF and CloudFront CDN are causing this issue as going direct to server results in this working correctly.

Anyone else ran into this?

Any ideas what that response means and how to address it?

Support ticket already raised:

[https://support.dynatrace.com/supportportal/browse/SUP-23380](https://support.dynatrace.com/supportportal/browse/SUP-23380)

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**Author:** ![skrystosik](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/skrystosik/32/21133_2.png) [@skrystosik](https://community.dynatrace.com/u/skrystosik)\
**Post date:** [April 27, 2019, 11:36am UTC](https://community.dynatrace.com/t/trying-to-do-rum-injection-but-receiving-an-odd-response-from-the-rb-post/20461/2 "2019-04-27T11:36:09Z")

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I think cookies are cut by WAF and this may be the issue.

Sebastian

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<div class="post-metadata">

**Author:** ![matthew\_eiseng1](https://dub1.discourse-cdn.com/dynatrace/user_avatar/community.dynatrace.com/matthew_eiseng1/32/10897_2.png) [@matthew\_eiseng1](https://community.dynatrace.com/u/matthew_eiseng1)\
**Post date:** [April 29, 2019, 10:07am UTC](https://community.dynatrace.com/t/trying-to-do-rum-injection-but-receiving-an-odd-response-from-the-rb-post/20461/3 "2019-04-29T10:07:33Z")

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Workaround for this was to manually add the domain in Application → Edit → Advanced Settings → Cookie and Header Settings → Domain to be used for cookie placement.

In this particular case the response on the POST ‘FL(apache,NoCookies)’ was a result of the domain inside the cookie only picking up the end ‘.co.uk’ instead of the domain ‘[mydomain.co.uk](http://mydomain.co.uk)’.