Vagrant 启动卡住了提示 “connection timeout retrying”

用的好好的，突然就无法启动了，我什么都没做啊，怎么办？

==> default: Clearing any previously set network interfaces...
==> default: Preparing network interfaces based on configuration...
    default: Adapter 1: nat
    default: Adapter 2: hostonly
==> default: Forwarding ports...
    default: 22 => 2222 (adapter 1)
==> default: Booting VM...
==> default: Waiting for machine to boot. This may take a few minutes...
    default: SSH address: 127.0.0.1:2222
    default: SSH username: vagrant
    default: SSH auth method: private key
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...
    default: Error: Connection timeout. Retrying...

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直接用virtualbox启动vm看一下启动报什么错