Urgent: InMobi mobile advertising SDK integration failing, what am I missing?

I am absolutely tearing my hair out trying to get InMobi's SDK integrated into my new mobile SaaS application. We just launched, and monetization through advertising is a critical part of our strategy, but this has brought us to a complete standstill for the past two days. I've been through their documentation countless times, and for the life of me, I cannot figure out why the ads aren't loading. It's incredibly frustrating to be stuck on what should be a straightforward integration.

The core issue is consistent failures during SDK initialization. Whether I'm trying to display a banner, interstitial, or rewarded video, the ads simply aren't displaying, and the callbacks consistently indicate failure. It feels like the SDK isn't even making successful ad requests to the InMobi mobile ad network.

Here's a detailed list of everything I've tried so far:

• I have meticulously followed the official InMobi documentation for both Android and iOS (I'm developing a cross-platform app, but facing issues on both).
• I've double-checked and triple-checked the Bundle ID, App ID, and Placement IDs in my code and on the InMobi dashboard. They are all correct.
• Confirmed that all necessary network permissions are present in AndroidManifest.xml (for Android) and Info.plist (for iOS).
• Experimented with different SDK versions, including the latest stable release and slightly older ones, to rule out version-specific bugs.
• Thoroughly checked device logs for any specific InMobi error codes or exceptions, but mostly getting generic initialization failures.
• Tested on various physical devices and emulators/simulators across different OS versions.
• For Android builds, I've reviewed ProGuard/R8 rules to ensure nothing is being obfuscated or stripped that shouldn't be.
• Checked for potential dependency conflicts with other libraries in my project, especially other ad networks or analytics SDKs, but haven't found anything obvious.

The specific symptoms are either a generic 'SDK initialization failed' message in the logs, or 'No Fill' errors, and the onAdLoadFailed callback is consistently triggered. I'm not seeing any successful ad requests going through, which suggests a deeper configuration problem rather than just a lack of inventory. It's like the SDK can't even connect properly to the InMobi backend.

I'm desperate for any guidance. Has anyone encountered similar issues with InMobi's SDK? Are there common pitfalls I might be overlooking—perhaps an obscure build setting, a crucial manifest entry, or a specific InMobi dashboard configuration that's easy to miss? I would immensely appreciate any advice from experienced InMobi integrators who have successfully navigated these waters. We really need to get our mobile advertising up and running quickly.

Waiting for an expert reply!