My Phone is failing to reconnect to the extender (only the 5 Ghz signal has this problem, the repeater hat its own SSID for both frequencies , 2,4ghz and 5 ghz) after being disconnected when i leave the house. it works only when i restart the repeater. The direct connection to the router wlan (a fritzbox 6660 cable) is working, I tried with assigning a fix IP adresse to the phone, it didn't help. When a deactivate my phone-WiFi  before leaving home and reactivate it when i am back, the reconnecting to the repeater is working perfectly. has anybody an idea what i can try more?

Update: the problem is also Happening when I disconnect and reconnect the WiFi manually in my phone