Channel closed


If I try to validate my blogpost I get “ERROR: Failed to fetch page due to: ChannelClosed” but I don´t know how to resolve. Can anyone help me please?

Regards Marlene

ERROR: Failed to fetch page due to: ChannelClosed

I tested the adress in your screenshot and everything seems to work now. I have the same problem and just wanted to ask if you know how to solve this problem?


I have been having the same problem with the twitter cards of my two websites for three days. I have not made any changes to any setting, and until now twitter cards worked perfectly. Now the links in the tweets show nothing, they appear as URL’s. Does anyone know how to solve the problem?


These are the url´s of the pages:


I still don’t have a solution, but maybe some information:

I testet the address in the screenshot of Couchabenteurer yesterday & it worked up until now- today not anymore.
I already mentioned that I have the same problem with my websites.

My url’s are:

When I tested the mentioned url’s in this forum using I detected that all url’s seem to be hosted at strato, similar to mine.
Another interesting point for me is that one of my url’s has an ssl certificate. When I test the domain using the https instead of http I get a different error. In one case of my subsites the TwitterCard even works.

This subsite has a playercard and makes it therefore an exception:

All the other subsites tested under https show:

INFO: Page fetched successfully
WARN: No metatags found

This isn’t a solution, but it indicates that it might be kind of a port issue between strato and twitter.
Maybe a filter at strato blocks a specific port or the IP of twitter. Otherwise it could also be that twitter blocks strato.


Hello, thanks for the information!!
My two websites are also hosted in strato. The question is: what would be the solution to this conflict? Maybe Twitter support can help us with this…


The solution depends on the cause. I am not sure if we as users can do much since the problem occures client independent. If twitter is the cause we can try to pressure their support.
If strato is the cause we would have to pressure the strato support. I am already in contact with strato but up until now they had no helpful information for me.
They told me to deactivate the server side spam filter, to look into the error log and sent me a link to this forum with quite old information to the ‘Channel Closed’ error shown here:

But for me nothing helped.
Later I told them about other strato domains with the same problems.
Their answer was that they checked my code and the code needed for the TwitterCards seems to be ok. They also said they had tested if anything is blocked by strato but that this isn’t the case. I should ask twitter and wordpress for further support…


And fascinating but true now the TwitterCards of Couchabenteurer seem to work again. Does she know the solution? Maybe we should try to contact her?


Hey, I can verify now, but if I tweet, the card doesn´t show up. So still no glue how to resolve the problem!


Oh hello,
interesting…but what did you have to do to get to this point?


ChannelClosed is an exception indicating a channel or socket has been closed. Potential causes may be IP filtering preventing Twitter’s IP range from fetching from the host. I’m unable to reproduce that locally so it looks like a probably fetching issue from the servers. The IP ranges are listed in the Cards troubleshooting documentation.

The reason for the sites failing with HTTPS is that they return HTTP 502 Proxy Error when accessed that way, with none of your site’s content. With HTTP, just the ChannelClosed exception.

I’m not aware of other causes at the network level, but interesting that these all appear to be on a related hosting provider.


I am also having the same issue. Site is also hosted at Strato. What are recommendations? - Page is

Thanks for any help!


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