The Trayn web app uses a secure connection for all data transfer between your browser and our servers. This secure connection requires that our server signs all out-going data with a certificate which is trusted by your browser. The certificated for our frontend are issued by Google, the certificates used by our backend server are issued by Let's Encrypt.
As of October 2021 Let's Encrypt started to sign their certificates with their new root certificate, which has been introduced in 2015. This means, if your operating system didn't receive any updates containing this new root certificate you will see a security warning when trying to access a website using a certificate issued by Let's Encrypt. There is a list with operating systems and browsers which are known to not work with the new certificate on the Let's Encrypt website: Certificate Compatibility
If you are using Safari or Google Chrome on Mac OS 10.11 or an older version - which didn't receive the new root certificate - here are some suggestions how you might resolve this issue:
Upgrade to Mac OS 10.12.1 or a newer version
Use a recent version of Mozilla Firefox
Install the new Let's Encrypt root certificate called ISRG Root X1
There's a comprehensive guide for how to install that certificate in the Let's Encrypt forums. But if you're affected from this problem, you probably also won't be able to access that website. So for your convenience here are the required steps to install the ISRG Root X1 certificate on Mac OS:
Download the certificate: https://letsencrypt.org/certs/isrgrootx1.der or if you can't access this URL use this copy: https://ranger.keybase.pub/certs/isrgrootx1.der
Open the certificate by double-clicking
isrgrootx1.derin the Finder. You'll get a "Add Certificates" dialog asking:Do you want to add the certificate(s) from the file "isrgrootx1.der" to a keychain?
In the drop-down "Keychain", select "login" (for just your user) or "system" (for all users).
Click "Add" to add it and close the "Add Certificates" dialog, leaving the Keychain Access window open for the next step.In the Keychain Access search box, type "ISRG". Find the ISRG Root X1, with the Keychain (login or system) that you added it. Double-click to open.
In the ISRG Root X1 dialog box, expand the "Trust" area.
For "When using this certificate", change "Use System Defaults" to "Always Trust". This will change other items as well
Close the dialog box, and verify with your login password or Touch ID