Azure Hub Expert Needed for Web Notification Issue

I'm experiencing an issue with my web notification delivery via Azure Hub. My web client hub registration completes successfully, but notifications sent from the Azure panel aren't going through and return an unknown error. I need this resolved quickly, as it should take no more than an hour for an expert.

Recent Changes:
- I have made some updates to the Azure configuration.
- I updated API keys and connection strings.
- I modified some tags or subscriptions in the notification hub.

Ideal Skills:
- Expertise in Azure Hub and its configuration
- Proficient in troubleshooting notification delivery issues
- Familiarity with Azure's API keys and connection strings
- Experience with modifying tags or subscriptions in notification hubs

Please note, I need this issue resolved as soon as possible.