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MySQL Error Unable to connect to any of the specified MySQL hosts when the MVC web service on Azure attempts to access a mysql server on the client's host
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fraziercpa@yahoo.com
0
Reputation points
The following error occurs when running a web service on the Azure platform that attempts to access a MySQL database hosted on the client's server:
Unable to connect to any of the specified MySQL hosts.
Azure App Service
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Shree Hima Bindu Maganti 4,155 Reputation points Microsoft External Staff Moderator2025-04-17T17:04:33.0166667+00:00 Hi @fraziercpa@yahoo.com
The error "Unable to connect to any of the specified MySQL hosts" when running a web service on Azure that attempts to access a MySQL database hosted on the client's server can occur due to several reasons.
First, ensure that the client's firewall allows inbound traffic on the MySQL port (default is 3306) and specifically permits connections from the outbound IP addresses of the Azure App Service. Next, verify that the MySQL server is configured to accept remote connections by checking that thebind-addressis set to0.0.0.0or the specific IP of the Azure app.
It's also important to confirm that the MySQL user credentials provided in the connection string are correct and that the user has been granted access from external hosts (e.g., using'user'@'%').
Additionally, ensure that DNS resolution is working properly from Azure to the client’s MySQL server by testing the hostname using tools likenslookupfrom the App Service’s console or an Azure VM.
If the client’s MySQL server is behind a NAT or VPN, it must be accessible over a public IP or connected through a secure tunnel like a Site-to-Site VPN or Azure VNet Gateway.
Lastly, review the MySQL server’s current connection load to ensure it hasn’t reached itsmax_connectionslimit, which could also prevent new connections. If applicable, consult Azure's documentation on outbound IPs and network integration to ensure proper connectivity.
https://learn.microsoft.com/en-us/azure/mysql/flexible-server/how-to-troubleshoot-common-connection-issues
https://learn.microsoft.com/en-us/azure/mysql/flexible-server/how-to-troubleshoot-connectivity-issues#diagnose-common-connectivity-errors
Let me know if you have any further assistances. -
fraziercpa@yahoo.com 0 Reputation points
2025-04-17T17:40:47.5766667+00:00 Thanks, Shree. I've already tried a few of your suggestions. I'll look into the others. This error appears to be common, and the message is quite specific.
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