Unable to add an Overdrive book to ADE

I found a solutuion that works on one of my old Macs (running El Capitain).

Read this article for a full explanation of the problem:

https://eclecticlight.co/2021/09/21/el-capitan-and-older-mac-os-x-are-about-to-have-a-security-certificate-problem/

There is a fix here:

https://docs.certifytheweb.com/docs/kb/kb-202109-letsencrypt/#macos-ios-etc

To perhaps save a bit oif time, I am cutting and pasting the text from this section:

macOS, iOS etc#

Some operating systems hold onto the expired R3 > DST Root CA X3 chain even if your server is no longer using it. Try a restart of the affected client device.

For older macOS not updated by Apple:

• Download the ISRG Root X1 certificate file from http://x1.i.lencr.org/
• Open the Keychain Access app and drag that file into the System folder of that app.
• Find the ISRG Root X1 certificate in System and double click on it, open the Trust menu and change "Use System Defaults" to "Always Trust", then close that and enter your password to confirm the change (if prompted).

I hope this helps!

I have the same problem. I am using Mac OS 10.7 on one of my computers so that I can continue to run some older software. When I tried to access a website from this computer after Oct. 1 via Chrome, I got a message that the clock on my computer was set ahead and therefore could not be verified through the security certificate. I looked into the problem further and found out that some certificate issuers have changed their protocols such that versions of the Mac OS prior to 10.12 will no longer be supported. Adobe's servers use the https proptocol, so I wondered if this issue might be connected to the Oct. 1 change. At the suggestion of the Adobe chat agent, I am going to contact Apple support to see if this might be the cause of the problem. I hope not because ADE is the only way to convert .acsm files from public libraries to .epub files for use on an ereader.