OverDrive for Mac no longer connecting?

Is anyone having connection problems when trying to download audiobooks using the old OverDrive for Mac desktop app?

I have OverDrive for Mac desktop app installed on an old Mac running High Sierra.

For the past couple weeks I've been having intermittent connection problems where the OverDrive app will throw an error message that says: "A connection to the Internet could not be established. Please check your Internet connection; you must be connected to the Internet to proceed with this download."

Up until today this cleared up after a few minutes or a few hours. But now it's been over 12 hours AND I can no longer connect to my library's OverDrive website. When I go to the website I get: "Error loading page ... there may be a network issue". But I can connect to other websites just fine and I can connect to the OverDrive website on my new Mac running macOS Sonoma.

I'm wondering if upgrading to Mojave (the last macOS that works with OverDrive for Mac) would fix this.

Or has OverDrive for Mac finally reached end of life?

Any insights appreciated.