I am sorry in the beginning for my weak English. Trying with a translator.
I have activation for "z3x tool pro" and I have one problem with reading codes in Samsung phones - I checked mainly on old c3530, c3250 phones.
Namely - there is a problem with reading codes or unlocking the phone from the "unlock" tab - I checked on different models, mainly old ones.
Every time after reading "security zone" it reads - and then when trying to upload "to security zone" there is an error - always.
After this error, you need to upload the soft again, because the phone does not start - all locks remain after uploading the new software.
This does not apply only to simlock, but all codes - the program does not complete the operation, there is an error halfway when trying to read the phone.
As much as you can, please contact me - how to do it - it is similar with every phone.