Unity Advertisement Legacy Fails to initialize in Build Java Class Not Found Services Banner

[Dsmithunity]

Hello everyone, I am posting here to seek help regarding the Advertisement Legacy package in Unity. I have searched heavily on this issue and the fixes/errors are not specific to me. Banner ads, and now rewarded ads have been implemented in my project, and work in the test mode in the Unity Editor, however when I build, I get errors on Ad Initialization, specifically:
Error | Unity | Initializing Unity Ads.
Error | Unity | (#0-#3) 0x727… (libunity.so) ? 0x0
Error | Unity | (#4-#11) 0x727… (libil2cpp.so) ? 0x0
Error | Unity | (#12-#25) 0x727… (libunity.so) ? 0x0
Error | Unity | (#26) 0x727… etc…
Error | Unity | Java.lang.ClassNotFoundException: com.unity3d.services.banners.IUnityBannerListener
Followed by another 24 similar errors.
Advertisement Legacy version is 4.12.0. Ad/Game IDs are correct and Test Mode is off. I figured I’d try here, finally, before just updating to the newer advertisement system.

[makaka-org]

This is a known issue… I didn’t observe any solution in multiple posts in Discussions.

Alternative solution:

Unity forces developers to integrate Unity Ads via Unity LevelPlay (New Standard in Unity). The Unity Ads as Unity package will not be updated. It was announced a long time ago.

I guess Legacy Ads 4.12 is the latest bounty is in updating this Unity package that can have bugs.

[Dsmithunity]

I’m glad it’s not just me. I look forward to trying the new ad system.

[makaka-org]

Try to clear all ads related stuff in your project manually before installing/ updating the new version. Source.

[Yasuyuki]

Hello,

Thank you for bringing this issue up. We’re aware of this issue and investigating it.
Our thought is that this problem comes from a third-party plugin such as EDM4U (External Dependency Manager for Unity).
Can you try to use Custom Main Gradle Template?

[Dsmithunity]

Hi, there. Thank you for this suggestion, I tried it with banner ads (Had to put them back in) and it did not work. I’m getting the same:

2024/09/12 19:06:29.539 28207 28236 Error Unity java.lang.ClassNotFoundException: com.unity3d.services.banners.IUnityBannerListener

[Yasuyuki]

Thanks for checking that.
The following thread could be related and shows a workaround.

Unity 6 Android Build fails due to Gradle version 8.4

Just tried out Unity 6.0 and surprisingly, upgrading the Unity version didn’t completely break down things! Managed to get the iOS build working on device! However, didn’t get the same success with Android build! On building the android platform, build fails with following grade error: What went wrong: A problem occurred evaluating project ‘:launcher’. Failed to apply plugin ‘com.android.internal.application’. The option ‘android.enableDexingArtifactTransform’ is deprecated. The current…

I hope this will help you. Our engineering team is still working on this issue, I will keep posting here if I get an update.

[VainM]

Are there any updates? I have tried every possible solution but still getting:

Error Unity Initializing Unity Ads.
Error Unity java.lang.ClassNotFoundException: com.unity3d.services.banners.IUnityBannerListener

Even without banner ads I am getting this error. Also any trick solution could help since I am stuck with this for days. I opened a new project and included only Advertisement Legacy sample to test and still this error… Unity version 2022.3.22f1, Advertisement Legacy version 4.12.0.