Very slow to connect to AP-one-AC-mini

Hi. I have a Surf Soho with the access point enabled. When I connect over WiFi to this point (mainly from Apple devices), the connection is very quick. I also have an AP-one-AC-mini in another part of the house connected by ethernet through a TP-Link router back to the Surf Soho. The mini has all the same access point settings (sames SSID and other parameters) as on the Surf Soho. The AP-one-AC-mini is in Bridge mode. In addition to my three VLANS, I have a management LAN defined on both boxes. This is set on the Ap-one-AC-mini under Network>WAN>WAN1>VLAN. I cannot find any way to identify the management LAN on the Surf Soho. When I connect from the same Apple devices via the AP-one-AC-mini, it takes several minutes to connect. Firstly it waits, then it states “no internet connection”, and displays a 192 IP address outside of any defined range, then eventually it connects. This happens every time on all the VLANS, but only when I connect via the AP-one-AC-mini. The TP-Link router is set to pass tagged traffic. Can you help please?