# Failed to trigger event because it does not implement the necessary interface

**URL:** <https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185>\
**Category:** Cinematics & Media\
**Tags:** sublevel, unreal-engine, question, Blueprint\
**Created:** [February 3, 2021, 10:31am UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185 "2021-02-03T10:31:58Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![SasMaster](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@SasMaster](https://forums.unrealengine.com/u/SasMaster)\
**Post date:** [February 3, 2021, 10:31am UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185/1 "2021-02-03T10:31:58Z")

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I implemented an ability to trigger events from the Cinematic Sequencer on the level blueprint. I followed this tutorial:

> **[How to activate event in level blueprint from level sequencer?](https://forums.unrealengine.com/questions/960755/how-to-activate-event-in-level-blueprint-from-leve.html)**
>
> I have created some nice behaviors in the level blueprint which activate on a keyboard binding. I now am trying to create a sequence where I want the event to trigger when it is reached in the sequence. For this I generate blueprint interface...

It works, but on each triggered even on the sequencer timeline I am getting the following warning:

> SequenceEvent\_\_ENTRYPOINTSequenceDirector\_0  
> BirdsMasterSequence Failed to trigger  
> event because it does not implement  
> the necessary interface. Function  
> expects a ‘OnSoundToText\_C’.

Now, I am not sure if I need to address this warning or discard. In my application I am using sub-levels.Each such a level has its own level sequencer triggering OnSoundToText event on the main level’s blueprint. Event function interface is called “OnSoundToText” and I do implement it per function in the sequencer BP. But I see that Unreal adds suffixes like “\_C” in runtime, probably to prevent naming collision between same function across different sub-levels an due to the interface name change in runtime it “doesn’t understand” to which interface it is related.  
I would like to understand if this is an issue I have somehow to handle or I can just discard it. I still haven’t packaged the app so I feel like I can get surprised there with such a bug.

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**Author:** ![Yee\_Tan](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Yee\_Tan](https://forums.unrealengine.com/u/Yee_Tan)\
**Post date:** [February 4, 2021, 12:40pm UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185/2 "2021-02-04T12:40:28Z")

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add event track from the green button +track rather than the dark grey button

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**Author:** ![SasMaster](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@SasMaster](https://forums.unrealengine.com/u/SasMaster)\
**Post date:** [February 13, 2021, 4:50pm UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185/3 "2021-02-13T16:50:36Z")

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I am not sure what you mean. That’s what I do. I use a separate “Event” track.

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**Author:** ![Jonathan.Devin](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@Jonathan.Devin](https://forums.unrealengine.com/u/Jonathan.Devin)\
**Post date:** [February 13, 2021, 7:17pm UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185/4 "2021-02-13T19:17:05Z")

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Implement the blueprint interface on all sub levels as well as the persistent level.

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**Author:** ![SasMaster](https://d3kjluh73b9h9o.cloudfront.net/original/4X/2/8/5/28502927f1d97ba1051b3b47ccfe17233bf41ef0.png) [@SasMaster](https://forums.unrealengine.com/u/SasMaster)\
**Post date:** [February 15, 2021, 8:43am UTC](https://forums.unrealengine.com/t/failed-to-trigger-event-because-it-does-not-implement-the-necessary-interface/478185/5 "2021-02-15T08:43:10Z")

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This solved the issue. Thanks.