Sometimes there are regional blocks in some provinces, that may be the case, can't test it. But they are not targeting simple numbers. Maybe some other keyword triggered a dynamic block in some regional ISP's GFW system. You can get those dynamic blocks easily by searching on Google for certain keywords. For the next 3 minutes your Internet will stop working.
If there is any Chinese involved in node, s/he could just write an email to the "internet police" gov't dept and ask them to lift the blocking, if it actually exists anywhere in the country.