1) In a new tab, type about:config in the address bar and press Enter. Click the button “promising to be careful”.
2) In the search box above the list type “dhe”
3) Double-click the security.ssl3.dhe_rsa_aes_128_sha preference to switch it from true to false
(4) Double-click the security.ssl3.dhe_rsa_aes_256_sha preference to switch it from true to false