If you're trying to connect to a computer or service via SSL and the connection is failing, you may need to update the certificates built into the WINC1500. By default it comes with many of the most popular SSL certificates but you may bump into a site that requires one that isnt included.
Its quite easy to update the certificates, you'll need to upload some code and run the uploaders but it only has to happen once
Start out by uploading the FirmwareUpdater sketch from WiFi101
If you are using a Feather M0 or WINC1500 breakout, don't forget to update the pins as necessary with setPins()!
If you are using a WiFi101 or WINC1500 shield, skip this step
and upload it!
After uploading be sure to note what is the name of the COM or Serial port for the Arduino Zero or Feather...You'll need this for the next step
Upload it to your Feather. Make sure the Serial console is not open before or after uploading.
Then select the Updater tool built into the IDE
Select the right COM port, and click Test Connection
If all is good you'll get a confirmation
Now at the bottom of the page, click Add Domain and type in the URL of the site you want to access:
Then click Upload Certificates
A few moments later...success!
Officially Atmel lists TLS 1.0 & 1.1, however we have noticed that the firmwares shipping on boards today seem to also support TLS 1.2 (verified by checking the results of www.howsmyssl.com).
The supported ciphers are: