Check that the remote FTP port is not blocked.

确认远程FTP端口没有阻塞。

youdao

Another place to check if a page has been blocked is within the page's HTML source code itself.

另一个检查网页是否已经被拦截的地方就是在网页源代码本身。

youdao

The researchers then staged an “incident” in which the camp’s water supply was cut off and all the boys had to check the water pipe (more than 1 km long) to see where it was blocked.

研究人员接下来安排了一个“事故”，他们切断了营区的供水。 所有的男孩子都要去检查水管（长度不止1公里），看看是不是有哪里堵住了。

youdao

If the White House is blocking former Justice officials from testifying about this program before Congress, and if the Justice Department's own investigators are blocked from auditing the policy, then what check is there on the president's power?

NPR: NSA Operations Remain Opaque to Investigators