Fastly, Google Cloud Functions & 503 SSL handshake error


I have been attempting to setup Fastly with Google Cloud Functions to provide a fast cache for my users internationally for common queries.

However, everything I have attempted has ended up with a
"Error 503 SSL handshake error".

I have managed to set it up fine on KeyCDN, you can see a googlers blog post about setting it up on keyCDN.

There isn’t any magic, it is straight forward and it just works. I’ve tried mucking around with all the SSL settings I can, including turning of verification of the certification. Nothing seems to work.

Has anyone else has luck with Google Cloud Functions + Fastly or know what the heck the SSL Handshake Error means?

Note: I am using the free SSL, so thats & both give the same error.


The 503 means that there was a handshake error when trying to connect to origin. Can you show me what your Origin settings are in the Fastly service you set up?


One of the great support staff at fastly @Richard_Alpagot figured it out.

The SNI had to be set to the same as the Certificate hostname.

Origins -> Host
TLS options:
Certificate hostname:
SNI hostname:

Settings -> Override Host:

I will play with the settings and configure it right and then make an update on what the best settings are.



I’m trying to setup fastly in front of google cloud functions as well, do you have any more info on your setup? domain, address/hostname, SNI values you used? the KeyCDN content you posted above seems to be depreciated, is your setup still working?