Interviewer not connecting to HTTPS on local server installation Certificate problem?

Good day,

I have setup my local installation on a Windows Server 2012 R2 running Survey Solutions 21.09.5, I am using Certify The Web to do my SSL certificates. We are having problems connecting tablets lower than Android 7 to the server.

as seen below

The diagnostic from the tablet is:

Version: 21.09.5 (build 29849)
SyncProtocolVersion: 7400
Device model: Lenovo TB3-X70F
Device type: Tablet
Android version: 6.0
DeviceId: 3d3cc1b739f412f0
RAM: 1.9 GB total, avaliable 28% (0.5 GB)
Disk: 11.3 GB total, avaliable 48% (5.4 GB)
DBSize: 263.7 KB
AcceptUnsignedSslCertificate: False
BufferSize: 4096
Timeout: 00:20:00
CurrentDateTime: 12/17/2021 2:14:54 PM
EventChunkSize: 1000
User: NONE

The newer tablets have been able to connect to the server however the bulk of our tablets OS are lower than Android 8.

Does any one know the steps for me to resolve this problem?



The problem unfortunately is the root certificate (again). Your certificate is signed by ISRG Root X1 and it was only included in Android 7.1.1. So all devices below that version will have the problem as they cannot trust the certificate they don’t know about.

Depending on which is more feasible you have two alternatives, manually install the root cert on all your Android 6 tablets; or replace your certificate with something that is trusted by older versions.
Let’s encrypt does have an alternative method of cross-signing certs to extend the support to Android 6 (Extending Android Device Compatibility for Let's Encrypt Certificates - Let's Encrypt) so perhaps the second option would be the best?

Certify the Web has an article outlining this as well: