Ad error 400 - 30% ad completion drop on Android

[Erik Sombroek]

Hi,

I'm working for a mobile gaming platform Poki.com.
Since the 15th of July we see a big drop in ad completion ratio specifically on Android (roughly 30%).

After a lot of debugging we found very inconsistent behaviour, on some Android devices it works and on some it doesn't work, 100% reproducible. (e.g. on a Xiaomi 9T).

We have spoofed the user agent from this phone via a desktop machine but this does not result in the issue.

Here you can see the result in the VAST tester:
https://share.getcloudapp.com/jkuZdlr4

A generic AdError 400.

Here you can see the vast URL compared on desktop versus mobile:
https://share.getcloudapp.com/L1uJokv6, the page returns a 400.

We thought it could potentially have to do with Audio, or interaction and have tested everything here. Here a test with NO sound and a clear interaction:
https://share.getcloudapp.com/8LuPBjQN

We have a strong believe that this could be something on Google's end. 

Would it be possible to verify this?

Kind regards,

Erik Sombroek

[Kasper Mol]

After more testing with this, the problem appears to be 100% reproducible in Chrome 84 on Android, and does not occur on older versions. 

Here is an example VAST tag: https://securepubads.g.doubleclick.net/gampad/ads?sz=640x360&iu=%2F21682198607%2Fmobile_ingame_rewarded_1%2F22_mobile_ingame_rewarded_1&ciu_szs&gdfp_req=1&env=vp&output=xml_vast2&cust_params=position%3DPR

So to reproduce:

- Go to VAST inspector on Android Chrome 84, attempt to run above ad, get a 400 video error.

- Do the same on Android Chrome 83, get a working video

- Do the same in any Desktop Chrome version, get a working video

[IMA SDK]

Hi,

Thank you for reaching out to us. I was able to reproduce the behavior that you're seeing with Ad Error 400 being fired on Android using Chrome 84. I ran your ad tag against our VSI on Chrome 84 browser, Samsung 8+ device and the SDK fired a 400 ad error code. However, the issue is not with the IMA SDK, it is being caused by the fact that the ad contains an .m3u8 (HLS) media file being picked by the SDK. One way to fix this issue would be to provide a list of mime-types supported by WebOs such as .mp4 and .webm. Feel free to take a look at our documentation for more details.

Regards,
Arnaud Casame
IMA SDK Team

ref:_00D1U1174p._5004Q22ZdlF:ref

[Kasper Mol]

Hi Arnaud,

Thanks for having a look at this so quickly. Setting the mimetype to `video/mp4` on mobile seems to indeed fix the problem. Interesting that this didn't cause any issues before the Chrome 84 release as I couldn't find anything in the release notes that points to this.

In any case, we'll be pushing this change and monitor whether it solves the problem.

Thanks again,

Kasper