In order for TURKTRUST SSL certificate to work properly, first you should install TURKTRUST Intermediate Root certificate.
You can download TURKTRUST Intermediate Root certificate from following link in CRT format;
http://www.turktrust.com.tr/sertifikalar/93_TURKTRUST_Elektronik_Sunucu_Sertifikasi_Hizmetleri.crt
Our SSL help pages explain how to create CSR and how to install TURKTRUST certificate step by step.
You can benefit from our help pages according to the system you are using.
If needed you can contact us via the following phone or e-mail;
SSL Certificate Services
0312 439 1000
ssl@turktrust.com.tr