Azure自动化Runbook无法连接至托管SQL实例问题求助

我最近跟着DP-300相关实验里的重建索引Runbook部署步骤，完成了Update-SQLIndexRunbook这个Azure自动化Runbook的配置。但现在碰到个头疼的问题：不管是手动运行这个Runbook，还是设置好计划任务自动触发，它都没办法成功连接到我的托管SQL实例，每次都会抛出连接错误：

Exception calling "Open" with "0" argument(s): "A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 0 - A connection attempt failed because the connected party did not properly respond aft...

有没有大佬遇到过类似的情况？能不能给点排查的方向或者解决思路呀？

备注：内容来源于stack exchange，提问作者LinuxGnut