BirdWeather PUC SIM card TLS errors

TLS and HTTP_CLIENT may show when trying to connect.

It appears to be a TLS/HTTP connection issue specific to the network providers, as the device works on other networks. The problem likely lies in the device's TLS/SSL handshake with the server, which is failing. Even if the modem successfully connects to the 4G network, the device still needs to create a secure tunnel to the BirdWeather server. This is where the process breaks down.

The log errors "esp-tls: Failed to open new connection in specified timeout" and "HTTP_CLIENT: Connection failed, sock < 0" indicate that the device is unable to establish a TCP/IP connection to the server. This isn't a problem with the modem's configuration or SIM card's ability to connect to the cellular network, but rather an issue with the device's ability to reach the intended destination through that network.

Resolution

Some networks such as Three and Vodafone may have a problem with a larger TLS record size (for example 16KB TLS record size). Check whether the device can use a lower TLS size and select that option. If you are unable to lower the record size please contact the device manufacture directly and explain that in order to connect you require a reduced TLS buffer size.

Examples of output

I (13790) PUC-APP: serverTime - 2025-08-01T16:00:39.709Z
I (13800) PUC-APP: check_set_time_from_server - 08-01-2025 16:00:39
I (13810) PUC-APP: Updating System Time & RTC_DS3231 from Server Time - 2025 7 1
I (13810) PUC-APP: Start - register_puc ( ) - 20250801_160039
I (13820) MAC address: MAC address: 7c:df:a1:f9:91:4c
I (13830) PUC-APP: macAddress - 7c:DF:A1:F9:91:4C
I (13830) PUC-APP: json_string
{
"macAddress":"7c:DF:A1:F9:91:4C",
"puc":true,
"hwVersion":"V8",
"gpsModel":"L86",
"bootCount":1501,
"fwVersion":"1.63"
}
W (74020) HTTP_CLIENT: Connection timed out before data was ready!
E (74020) PUC-APP: (BirdWeather) Error esp_http_client_perform ESP_ERR_HTTP_EAGAIN
I (74020) PUC-APP: HTTP_EVENT_DISCONNECTED
W (74030) PUC-APP: Not Connected to Server -- Loading SPIFFS and NVRAM

W (73890) esp-tls: Failed to open new connection in specified timeout 
E (73890) transport_base: Failed to open a new connection 
E (73890) HTTP_CLIENT: Connection failed, sock < 0 
E (73890) PUC-APP: (BirdWeather) Error esp_http_client_perform ESP_ERR_HTTP_CONNECT 
I (73900) PUC-APP: HTTP_EVENT_DISCONNECTED 
W (73910) PUC-APP: Not Connected to Server -- Loading SPIFFS and NVRAM