My raspberry pi 3b (running jessie) fails to connect to wifi.

It can scan the networks, and finds all nearby wifi SSIDs. When i try to connect and enter the password, nothing happens (credentials are correct 100%).

I've tried using the same SD card onto another rpi, and not had this issue, which is why i think it must be a hardware issue.

Also, ifconfig shows:

```
wlan0     Link encap:Ethernet  HWaddr b8:27:eb:0f:b9:7a  
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:1526 errors:0 dropped:1526 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000 
          RX bytes:341915 (333.9 KiB)  TX bytes:0 (0.0 B)

```

`RX packets:1526 errors:0 dropped:1526` seems strange to me, right?
Is it just broken? Or am i missing something?

I've tried using the same SD card, and same power supply on other RPIs and not had this problem.

Also worth saying that i have 4 routers here which i can use. The same problem is happening when connecting to any of them.

As suggested by ingo i looked at the journal using journaltctl -e -b. Below are some extracts that may be relevant.

```
Dec 09 12:23:06 raspberrypi kernel: brcmfmac: brcmf_add_if: ERROR: netdev:wlan0 already exists
Dec 09 12:23:06 raspberrypi kernel: brcmfmac: brcmf_add_if: ignore IF event
Dec 09 12:23:06 raspberrypi kernel: IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
Dec 09 12:23:06 raspberrypi kernel: brcmfmac: power management disabled
Dec 09 12:23:06 raspberrypi networking[271]: Configuring network interfaces...done.
Dec 09 12:23:07 raspberrypi systemd[1]: Started LSB: Raise network interfaces..
Dec 09 12:23:07 raspberrypi systemd[1]: Starting ifup for wlan0...
Dec 09 12:23:07 raspberrypi systemd[1]: Started ifup for wlan0.
Dec 09 12:23:07 raspberrypi wpa_supplicant[422]: Successfully initialized wpa_supplicant

Dec 09 12:23:12 raspberrypi kernel: brcmfmac: brcmf_sdio_hdparse: seq 166: sequence number error, expect 165
Dec 09 12:23:12 raspberrypi kernel: brcmfmac: brcmf_sdio_hdparse: seq 165: sequence number error, expect 167
Dec 09 12:23:12 raspberrypi kernel: brcmfmac: brcmf_sdio_hdparse: seq 167: sequence number error, expect 166

Dec 09 12:24:33 raspberrypi wpa_supplicant[435]: wlan0: Trying to associate with SSID 'Vodafone ML4G 1844'
Dec 09 12:24:33 raspberrypi wpa_supplicant[435]: wlan0: CTRL-EVENT-ASSOC-REJECT status_code=16
Dec 09 12:24:34 raspberrypi wpa_supplicant[435]: wlan0: Trying to associate with SSID 'Vodafone ML4G 1844'
Dec 09 12:24:35 raspberrypi wpa_supplicant[435]: wlan0: CTRL-EVENT-ASSOC-REJECT status_code=16
Dec 09 12:24:36 raspberrypi wpa_supplicant[435]: wlan0: Trying to associate with SSID 'Vodafone ML4G 1844'
Dec 09 12:24:37 raspberrypi wpa_supplicant[435]: wlan0: CTRL-EVENT-ASSOC-REJECT status_code=16
Dec 09 12:24:38 raspberrypi wpa_supplicant[435]: wlan0: Trying to associate with SSID 'Vodafone ML4G 1844'
Dec 09 12:24:39 raspberrypi wpa_supplicant[435]: wlan0: CTRL-EVENT-ASSOC-REJECT status_code=16
Dec 09 12:24:39 raspberrypi wpa_supplicant[435]: wlan0: CTRL-EVENT-SSID-TEMP-DISABLED id=1 ssid="Vodafone ML4G 1844" auth_failures=1 duration=10 reason=CONN_FAILED

```

Just looked for anything including wlan0 or brcmfmac.