Distance of LX200V20

Hello, we are using the LX200V20 in our new version of the ethernet extender.
Last week we tested the data rate of the new version and the old one and got the results that the new version with the LX200V20 doesn’t work as well as the old ethernet extender.
The new version works only up to 225m but it should work over 300m. We wondered about it and would be pleased if you could help us to find the case why it does not work.

For the test we used one twisted pair of a CAT5E.

Could you reach with the LX200V20 farther distances than 225m? Do you have a diagram which shows data rate vs. cable length?

In the PCB layout above you can see how we have decided to place the different parts of circuit onto our board. Do you think the ethernet magnetics are placed to near to the transformer? Or is the power supply maybe to near to the LX200V20?

kind regards VJ