Blackberry Tablet never succeeds with one UK Site

[#1]

Network Error:

Anyone any clues why I have 1 site (www.aldi.co.uk) that always work on my laptops via my PN Router, but
on my Blackberry Playbook always shows "Network Error" message as image.
If I modify address to aldi.com that works as do all the countries listed, except Great Britain link?
Any suggestions re this annoying behaviour appreciated

[#2]

With the latest Firefox, that website works for me,
However with an old version of Firefox, I get -

Quote

Secure Connection Failed An error occurred during a connection to www.aldi.co.uk. Cannot communicate securely with peer: no common encryption algorithm(s). (Error code: ssl_error_no_cypher_overlap) The page you are trying to view cannot be shown because the authenticity of the received data could not be verified. Please contact the web site owners to inform them of this problem. Alternatively, use the command found in the help menu to report this broken site.

I wonder whether Aldi have removed SHA-1 certificates, and are only using the new SHA-2/SHA-256 hashed security certificate for their website, and therefore now fails to load on older browsers which don't and won't have support for that.
https://blog.cloudflare.com/sha-1-deprecation-no-browser-left-behind/

Can you update the browser on your Blackberry to a current version ?

[#3]

Thanks all; no the Playbook hardly get any support now;