I am encountering an issue where one of the microservices in my project is failing, resulting in 500 HTTP errors and a System URI Format Exception error in Azure Application Insights. To resolve this, I noticed the same System URI Format Exception when accessing my storage account through Azure Storage Explorer.

To address the issue, I changed the primary connection string of my storage account (used in my code through Key Vault secrets) by replacing the secondary connection string in Key Vault with the primary one. After restarting the app service causing the error, everything seemed to work fine.

However, whenever I restart my app services, the same System URI Format Exception error reoccurs. Restarting only the affected app service does not resolve the issue.

I have contacted Microsoft support via email, but they are also unsure of the root cause, suggesting it might be a code issue. However, I don’t believe this is the case because we haven’t changed anything in the code. If it were a code issue, the application should not be working now. Additionally, I have enabled diagnostic settings in my storage account, and the alternatives are successful, indicating it might be a Key Vault issue.

If anyone has any ideas on how to resolve this issue, please let me know.