Can't access uk.yahoo.com or mail.yahoo.com

[#1]

I'm stumped with this one. I can't access uk.yahoo.com or mail.yahoo.com though news.yahoo.com and the rest of the interent work fine.  I get a browser error message "this page is not available" or "the connection was reset" depending upon the browser. If I open a CMD window I can ping them ok, and the DNS lookup is fine.
This is true of all PCs and Smartphones (iOS or Android) in the home. However if I open a VPN to my employer the services work fine. The common factor seems to be either plusnet broadband or my router. The router is a Huawei EchoLife Home Gateway. I've been through all the router settings - I can't see anything that might stop Yahoo.
Any ideas please?

[#2]

What happens if you try a tracert to them ?
Here's mine for reference (uk.yahoo.com)

Tracing route to ds-any-fp2.wa1.b.yahoo.com [77.238.160.51]
over a maximum of 30 hops:
  1     4 ms     3 ms    21 ms  192.168.1.1 
  2    18 ms     9 ms    16 ms  lo0-central10.ptw-ag02.plus.net [195.166.128.196] 
  3    11 ms     7 ms     9 ms  link-a-central10.ptw-gw01.plus.net [212.159.2.148] 
  4     8 ms     9 ms     9 ms  xe-0-2-0.ptw-cr01.plus.net [212.159.0.248] 
  5    14 ms    25 ms     8 ms  ge-1-1-0.pat1.the.yahoo.com [195.66.224.129] 
  6    20 ms    15 ms    30 ms  so-0-0-0.pat1.ams.yahoo.com [66.196.65.86] 
  7    53 ms    39 ms    40 ms  xe-0-1-0.msr1.ch1.yahoo.com [66.196.65.69] 
  8    39 ms    43 ms    38 ms  te-8-4.bas-a2.ch1.yahoo.com [87.248.127.11] 
  9    47 ms    46 ms    45 ms  ir2.fp.vip.ch1.yahoo.com [77.238.160.51] 
Trace complete.

[#3]

Mail.yahoo.com redirects to login.yahoo.com. The trace route looks OK I think.
More baffling is that it appears to be intermittent. I managed to load yahoo.com a few times, then later it's broken again.

C:\Users\Home>tracert login.yahoo.com
Tracing route to eu-eulogin.lga1.b.yahoo.com [217.146.187.123]
over a maximum of 30 hops:
  1     2 ms     1 ms     1 ms  192.168.0.1
  2    25 ms   160 ms    25 ms  lo0-central10.pcl-ag03.plus.net [195.166.128.184
]
  3    25 ms    24 ms    27 ms  link-b-central10.pcl-gw02.plus.net [212.159.2.17
0]
  4    48 ms    24 ms    24 ms  xe-10-2-0.pcl-cr02.plus.net [212.159.0.202]
  5    24 ms    23 ms    25 ms  ae1.ptw-cr02.plus.net [195.166.129.2]
  6    25 ms    25 ms    24 ms  195.66.236.129
  7    43 ms    33 ms    24 ms  ge-0-1-0.pat1.the.yahoo.com [66.196.65.28]
  8    41 ms    35 ms    42 ms  UNKNOWN-66-196-65-X.yahoo.com [66.196.65.17]
  9    37 ms    39 ms    41 ms  ae-2.msr1.ird.yahoo.com [66.196.67.235]
 10    35 ms    41 ms    42 ms  te-7-4.bas-a1.ird.yahoo.com [217.146.191.217]
 11    37 ms    66 ms    37 ms  l1.login.vip.ird.yahoo.com [217.146.187.123]
Trace complete.

[#4]

Solved (sort-of). I replaced the horrid Huawei EchoLife router with my ancient Netgrear DG834G. Yahoo mail now works. I've no idea why the EchoLife would block yahoo connections...
Thanks DomS for your suggestion.

[#5]

I had a similar problem a couple of years ago; my DLink router wouldn't connect with Microsoft sites!!!
Exchanged emails/posts with Bob Pullen but nothing worked -til I swapped to an old Buffalo router -never did get the bottom of it -way beyond my technical expertise