Indesign export to epub error

[defaultbpgkg3n7ogjs]

Hi team, I'm getting the following error when I upload my epub file created in InDesign to Ingram Sparks platform for publishing. I have tried to re-make the Table of Contents / Navigation but it didn't fix my problem. Any ideas what the issue could be?

Error while parsing file: element "a" missing required attribute "href

[BobLevine]

Roll back to 20.0.1. I know that one doesn't have the export bugs.

[defaultbpgkg3n7ogjs]

Thank you! I will give that a try