当数据库用户不存在时，将弹出此消息。比较此处的手册。

多个本地数据库 不能作为说明。角色在群集范围内有效。再次手册：

This message pops up, when the database user does not exist. Compare the manual here.
Multiple local databases cannot be the explanation. Roles are valid cluster-wide. The manual again:

请注意，角色是在数据库集群级别定义的，因此
在集群中的所有数据库中均有效。

Note that roles are defined at the database cluster level, and so are valid in all databases in the cluster.

您必须以另一个数据库集群结尾。那将是在同一台计算机上运行的另一台服务器，侦听不同的端口。或者更有可能在另一台机器上。

You must be ending up in another database-cluster. That would be another server running on the same machine, listening to a different port. Or, more likely, on a different machine.

消息是否实际上来自远程服务器？

Could it be that the message comes, in fact, from the remote server?