Wifi Extender to Mikrotik RB951Ui-2HnD, 150ft direct LOS

I am having an issue that I do not know how to search for. The issue I am having is I have a WiFi repeater in a window in 'Building A' 150ft away with direct LOS to a window in 'Building B'. The WiFi extender is pushing out a great signal from one window to the other. The signal drops as I walk around 'Building B'. I would like to setup this MikroTik 951Ui in that 'Building B' window. I am guessing that this is a DHCP issue on the router in 'Building A' coming across the extender.

How do I make this work?

EDIT:

I tried putting the MikroTik in Building B in repeater mode but it cannot grab the wireless from Building A. It gets stuck on "Starting" when I try it.

Thank you..