Update cert.h

[eMadman]

Still throws an error when trying to connect to check for newer firmware

[ 6772][E][ssl_client.cpp:36] _handle_error(): [start_ssl_client():263]: (-9984) X509 - Certificate verification failed, e.g. CRL, CA or signature check failed
[ 6774][E][WiFiClientSecure.cpp:135] connect(): start_ssl_client: -9984

[doudar]

There's something like a "master" certificate you could look for, also make sure it's for the proper GitHub domain as referenced by the firmware url in settings.h

I remember having to try a couple different ones when auto updates were first implemented. Possibly @MarkusSchneider has some insight in what certificate to use?

[eMadman]

Reverted the changes - after digging, the original is on the correct cert - Github's using

DigiCert SHA2 High Assurance Server CA

[eMadman]

Adding all the Digicert certificates seems to fix it. Sent it out to two users for testing
firmware.zip

[doudar]

Can you please add a note in cert.h where you got the new ssl from for future reference?

Also need an update to the changelog.

Great work!

[doudar]

Approved, but check the notes above before you merge.

Thanks!

[MarkusSchneider]

@eMadman You finally solved it 👍.
Last time when I created a certificate I got 3 files. I combined all files into one crt file.
I've got a root-ca certificate, intermediate certificate and the new certificate for my application. root-ca certificate and intermediate certificate are necessary to build the chain of trust to a trusted Root CA.

See here for more details: https://www.keyfactor.com/blog/certificate-chain-of-trust/

Good work.

[eMadman]

Ready to merge - pending feedback from another user before I click it.

[eMadman]

I'm comfortable with the changes at this point. Tested on a couple more units - successful attempts at reaching github and downloads of the HTML files