Error establishing connection with ESP8266 (ESP12)

[2color]

I'm having difficulties getting an ESP12 to connect. I've followed the instruction carefully and uploaded the root certificates. I also created the device and configured everything on the Google Cloud end.

The ESP connects to the wifi but then restarts.

I tried running the same configuration on an ESP32 and it worked immediately.

What is the correct SSL Support setting?

When configured to Basic I see the following in the console:

[hostByName] request IP for: mqtt.2030.ltsapis.goog
[hostByName] Host: mqtt.2030.ltsapis.goog IP: 64.233.184.206
:ur 1
:del
:ref 1
BSSL:_connectSSL: start connection
BSSL:Connection *will* fail, no authentication method is setup
:wr 115 0
:wrc 115 115 0
:ack 115
:rn 7
:rcl
:abort
:rd 5, 7, 0
:rdi 7, 5
:rd 2, 7, 5
:rdi 2, 2
:c0 2, 7
BSSL:_wait_for_handshake: failed
BSSL:Couldn't connect. Error = 'Unknown error code.'

With all SSL chipers are enabled I get the following error:

FATAL ERROR: BSSL stack overflow

User exception (panic/abort/assert)
Abort called

>>>stack>>>

ctx: bearssl
sp: 3fff1f14 end: 3fff1f94 offset: 0000
3fff1f14:  00002ad5 000000d5 00000004 deadbeef  
3fff1f24:  000000fe 00000000 00000000 00000000  
3fff1f34:  00000000 00000000 00000000 3fff1f64  
3fff1f44:  00000004 00000090 00000004 00002ad5  
3fff1f54:  00003a98 00000000 3fff0844 40209fc6  
3fff1f64:  3ffe8d4a 0000003e 00000000 40209fdc  
3fff1f74:  40258801 3fff35b0 deadbeef 40209055  
3fff1f84:  deadbeef 00000000 3fff0844 40204ce0  

ctx: cont
sp: 3ffffdd0 end: 3fffffc0 offset: 0000
3ffffdd0:  00003a98 00000000 00000008 40207b9a  
3ffffde0:  000005f3 00000005 a7b12ee2 00000000  
3ffffdf0:  00000001 000016b7 3fff2dbc 40221e86  
3ffffe00:  3fff32bc 3fff20b4 3fff2dbc 00000001  
3ffffe10:  00000001 00000001 3fff0844 40207dd8  
3ffffe20:  3fff20b4 00000000 3fff0844 40207fbb  
3ffffe30:  00000023 3ffef974 00000001 40209a9f  
3ffffe40:  00000000 00000000 00000000 4020a0b7  
3ffffe50:  00000000 3fff2314 3fff0844 40206bb0  
3ffffe60:  000022b3 00000d50 3fffff00 3fff1fcc  
3ffffe70:  000022b3 3fff0844 3fff20b4 3fff1fcc  
3ffffe80:  000022b3 3fff0844 3fff20b4 402080d9  
3ffffe90:  4020c0b8 ceb8e940 4020c0b8 ceb8e940  
3ffffea0:  3fff2abc 3ffe8b4b 00000000 40208654  
3ffffeb0:  40208a4c 000000ce 3fffff30 4020940c  
3ffffec0:  3fff29dc 3ffeedac 3fffff30 402095cc  
3ffffed0:  00000000 3ffeedac 3fffff30 402095fc  
3ffffee0:  3ffeedac 3ffeedac 3ffef7d4 40208e44  
3ffffef0:  00000000 3ffeedac 3fffff30 40202222  
3fffff00:  3fff2384 00000000 80fe002f 6a6f7200  
3fffff10:  73746365 80fe002f 3fff206c 3fff1fcc  
3fffff20:  00000000 3ffef7d4 3fff206c 40202c99  
3fffff30:  3fff2abc 00ce00cf 00133400 3fff2384  
3fffff40:  0053005f 001334b8 3ffef974 00000000  
3fffff50:  3fff2384 3ffef974 0000000a 3ffef914  
3fffff60:  402417e2 042c1d80 3fff0844 3ffef914  
3fffff70:  3fffdad0 00000000 3ffef7b4 4020231a  
3fffff80:  3fffdad0 00000000 3ffeedd4 4020245c  
3fffff90:  3fffdad0 00000000 3ffef7d4 40202409  
3fffffa0:  feefeffe 00000000 3ffef8d4 40209bcc  
3fffffb0:  feefeffe feefeffe 3ffe8500 40100f39  
<<<stack<<<

[gguuss]

Good to hear your configuration is confirmed on the ESP32.

I have had success with either SSL configuration, what version of the Esp8266 SDK are you using (latest should be 2.6.1)? Also, how are you specifying the root certificate (static bytes in ciotc_config.h or SPIFFS)?

[gguuss]

I encountered the same issue and have gotten to the bottom of it:

• You need to enable all cyphers to connect
• You need to modify the memory allocated to BearSSL

To increase memory settings, see this change to Arduino/cores/esp8266/StackThunk.cpp. I hope this gets improved in a future release.

[2color]

Thanks @gguuss I'll give that a go.

How do I enable all cyphers?

[DanielGarc]

I encountered the same issue and have gotten to the bottom of it:

You need to enable all cyphers to connect
You need to modify the memory allocated to BearSSL
To increase memory settings, see this change to Arduino/cores/esp8266/StackThunk.cpp. I hope this gets improved in a future release.

I tested this today, as I was getting random resets until successfully connected. I discovered that the amount of bytes in the stack required to connect to the google lts server is more than the amount merged by Expand BSSL stack #6819

Right now I'm getting a max usage of:
BSSL stack: 6132
and the commit increased the stack to:
#define _stackSize (5900/4)

Thanks @gguuss I'll give that a go.

How do I enable all cyphers?

If you are using PlatformIO, cyphers are enabled by default
If you are using the Arduino IDE :

[2color]

Thanks @DanielGarc