# Action does not implement the IFBCustomAction interface
**URL:** https://www.finalbuilder.com/forums/t/action-does-not-implement-the-ifbcustomaction-interface/2547
**Category:** Discussion
**Created:** [June 8, 2017, 3:28am UTC](https://www.finalbuilder.com/forums/t/action-does-not-implement-the-ifbcustomaction-interface/2547 "2017-06-08T03:28:06Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@beran](https://www.finalbuilder.com/forums/u/beran)
#### Post date: [June 8, 2017, 3:28am UTC](https://www.finalbuilder.com/forums/t/action-does-not-implement-the-ifbcustomaction-interface/2547/1 "2017-06-08T03:28:06Z")
I use Final Builder 8 build 8.0.0.2083
I add new Custom Action and Implement it in my .NET project. However, when I try to add it to Final builder project and run it, I got this error:
**Error Executing Action: Action does not implement the IFBCustomAction interface**
What can be a problem here?
Thanks for any help.
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### Author:  [@nevar](https://www.finalbuilder.com/forums/u/nevar)
#### Post date: [June 13, 2017, 1:35am UTC](https://www.finalbuilder.com/forums/t/action-does-not-implement-the-ifbcustomaction-interface/2547/2 "2017-06-13T01:35:41Z")
Hi Anderi,
If you could send your custom action to [support@finalbuilder.com](mailto:support@finalbuilder.com) we will be able to assist you more with this issue.
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### Author:  [@beran](https://www.finalbuilder.com/forums/u/beran)
#### Post date: [June 13, 2017, 12:41pm UTC](https://www.finalbuilder.com/forums/t/action-does-not-implement-the-ifbcustomaction-interface/2547/3 "2017-06-13T12:41:16Z")
Hi Jason,
I figured it out, why I got this error. It’s because I use wrong CustomActionApi.dll. Now it’s all working correctly