no access to WLAN device from LAN

Hi,
cAP ac configured as access point.
Applications in m LAN cannot reach my mobile phone (connected to WLAN Port) . This used to work with my old (and otherwise lousy) ???-Router (no bashing).
Any hint, what I did mess up or miss?

TIA
Michael

Does your phone have a charged battery?
Just making a point, with basically no information, even my expensive crystal ball is useless.