Why don't pass-through adapters work?

Question

network hardware

On the one hand, Mikrotik, on the other hand, a computer with a Realtek built-in network card. There is an Internet cable from Mikrotik, but it is not enough. It is logical to lengthen it, for this purpose I bought a pass-through adapter. I connected another network wire to the computer
and connected them:
https://technopoint.ru/product/bfafedbaa8990340/pr... to 100mbit, and sometimes immediately to gigabit.
I also tried this one - https://anlan.ru/catalog/51729 here stupidly writes that the cable is not always plugged in. What's wrong? What could be more precisely wrong, tell me where to dig?

Answer 1

What is the total length of the resulting cable?

Answer 2

Check that both cables are crimped correctly