@Gil1 

Hi,

According to the firmware download page for the RE355 V1 the AP Mode feature was added in the year 2018.

https://www.tp-link.com/en/support/download/re355/#Firmware

If you still have the old firmware from 2015, then you need to update in order to have AP Mode available.

  @Gil1 

Many thanks. It worked. I could not find the firmware on my own so I  really aprreciate it.

However, I cannot get a download speed of faster than 100 mbps once connected as an access point with a cat 5e cable to my main router which produces a download speed of 600 mbps. Any ideas why?

Thanks again,

Gil

  @Gil1 

Is your router able to show link speeds for its LAN ports? (either within its GUI or via indicator lights on the ports themselves)

If yes, does it show a link speed of 1000 Mbps (or 1 Gbps) for the LAN port where the RE355 is connected?

  @woozle 

Thanks a lot again.

My bad.

I connected it through my Moca connector which is capped at 100 Mbps.

I have tried through my AX1800 and indeed got a gigabit connectetion negotiated and managed to get a download speed of nearly 600 as my wired devices.

Thank you very much - you have been a great help.

Gil