continiously disonnect reconnect / status_led wrong ?

[starbrights]

Do have two board, a D1 mini and a wroom-02 (with battery holder). Although configured both same way, the wroom-02 doesn't work (the same way). I get continuously:

scandone
no >my SSID< found, reconnect after 1 s
disconnect from >my SSID<, reason 201
reconnect

That's bit weird as type "scan" as a single command delivers me my ssid (and some others)?!?

I found that status_led might be at different position.
While it it "2" ind D1, it should be "16" in wroom-02?!?
But even after set this (and save), behaviour keeps same.

Might there be another GPIOs doing something different and disturb operation?

Doing disconnect and connect gives me some more details, but I don't understand it's meaning:

...
reconnect
state: 2 -> 0 (0)
scandone
state: 0 -> 2 (b0)
state: 2 -> 3 (0)
state: 3 -> 5 (10)
add 0
aid 5
cnt 
state: 5 -> 2 (2a0)
rm 0
disconnect from ssid >my SSID<, reason 2
reconnect

[starbrights]

That is really weird. I do settings in serial terminal

set ssid 
set password 
set ap_ssid 
set ap_password 
set status_led 16
save

... of course with my vaules. Works on D1, but not on Wroom-02.
If I cange the ssid/password to some other router it works, but extremly slow (0.1..0.3MBit instead of 5MB).

I can't think any reason why same software behaves so different. One could think is is some hardware problem, but I can run this device (with some other software) to send sensor data to an MQTT broker. So it can connect to the Router and keep connection.
There is no source code to check what the states and reasons mean.
Why there is connection to the other router (although slow), but not to my first one? Antennna seems to be ok, STA RSSI: -74

Edit:
As the boards with battery holder attached are so useful, I bought another one that has same behavior. So it doesn't seem a defect on a particular board but something more systematic. HELP!