Receiving connection timeouts to SQL Server from app running in staging deployment slot

Question

For some reason, I'm receiving new connection timeout issues in a deployment slot for my Azure app service. This is despite me having not changed anything network-wise, the primary deployment slot not having a connection issue, and me being able to connect to the database from my workstation just fine. I am not using any vnets.

Any idea how this could be happening?

 ConnectionError: Failed to connect to <mydb>.database.windows.net:1433 in 15000ms
 at /home/site/wwwroot/node_modules/mssql/lib/tedious/connection-pool.js:85:17
 at Connection.onConnect (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1012:9)
 at Object.onceWrapper (node:events:629:26)
 at Connection.emit (node:events:514:28)
 at Connection.emit (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1040:18)
 at Connection.connectTimeout (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1254:10)
 at Timeout._onTimeout (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1199:12)
 at listOnTimeout (node:internal/timers:569:17)
 at process.processTimers (node:internal/timers:512:7) {
 code: 'ETIMEOUT',
 originalError: ConnectionError: Failed to connect to ifhc.database.windows.net:1433 in 15000ms
 at Connection.connectTimeout (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1254:26)
 at Timeout._onTimeout (/home/site/wwwroot/node_modules/tedious/lib/connection.js:1199:12)
 at listOnTimeout (node:internal/timers:569:17)
 at process.processTimers (node:internal/timers:512:7) {
 code: 'ETIMEOUT',
 isTransient: undefined
 }
 }

Answer 1

Hello @Jacob Page !

Welcome to Microsoft QnA!

Facing some issues on WebApp connectivity considering nothing has changed could have a lot of reasons.

First of all examine all your logs and try to activate Application Insights for a period of time to drill better into logging

Use the "Diagnose and solve problems" , https://learn.microsoft.com/en-us/azure/app-service/overview-diagnostics

Check Service Status for you region might be something else on Azure not your fault

Check Service Limits , it could be a limit you reached , highy unlikely but worth checking https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/azure-subscription-service-limits

Upgrade your Plan to another Tier and check the behavior , you can do that easily !

https://learn.microsoft.com/en-us/azure/app-service/app-service-plan-manage#move

If nothing comes up , check with Azure Support !

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I hope this helps!

Kindly mark the answer as Accepted and Upvote in case it helped!

Regards