Python加载数据集时由于连接方在一段时间后没有答复或连接的主机没有反应，链接尝试失败

Python加载数据集时由于连接方在一段时间后没有答复或连接的主机没有反应，链接尝试失败
这是什么原因

def DentateGyrus_scvelo(
    url="https://www.dropbox.com/s/3w1wzb0b68fhdsw/dentategyrus_scv.h5ad?dl=1",
    filename="dentategyrus_scv.h5ad",
):
    """The Dentate Gyrus dataset used in https://github.com/theislab/scvelo_notebooks/tree/master/data/DentateGyrus.
    This data consists of 13, 913 genes across 2, 930 cells.

    Note this dataset is the same processed dataset from the excellent scVelo package, which is a subset of the DentateGyrus dataset.

    Returns
    -------
        Returns `adata` object
    """

img


img

确定一下网络是否连通？

img