Hi Al •,
Welcome to Microsoft Q&A forum.
As I understand, your Azure MySQL Flexible Servers Deployment is taking a long time/ Unable to delete VNet/Subnet due to serviceAssociationLinks.
There could be any of the following reasons due to which the deployment is taking long:
1). Check Resource Limits there could be subscription-based limits on the deployment of resources.
2). Try to delete the VNet or subnet again using Azure CLI or PowerShell. You can use the following command to force deletion if necessary:
az network vnet delete --name <vnet-name> --resource-group <resource-group-name> --yes
3). You can check if there is any Region-specific temporary outage which could also make it long.
4). Check existing Network Settings if they are correct.
Let us know if this helps or have queries.
Thanks