First of all, Akeeba is a great product and very happy user for some years now.
This is the first time that I'm a bit at a loss after multiple weeks of troubleshooting.
Until 29/02/2020 backup configuration was working normal as expected. Both manual as scheduled via Cron. As of 01/03/2020 I noticed that no scheduled backup are taken anymore. Manually taking a backup still works as expected for both my profiles (local and ftp backup). Also the automatic backup as part of updating Joomla Core is also working.
Other Cron jobs are also still working. When I run the scheduled command, I get an error as can be observed in attached image (2020-04-13_13-38-28.jpg).
Another symptom is that when I try to access the "Schedule Automatic Backups" via the control panel, I'm getting the same error concerning the Model in the browser.
In order to trying to fix the issue I decided to try to update the version. As it was also indicated by the plugin version check. Unfortunately the update is not working either. When using the wizard I get a copy file failed error. This is strange because update to 7.1.0 worked fine. Also other plugin updates operate without errors.
To solve this update issues I went over the troubleshooting steps from your documentation and none of the items worked. I even tried to upload the content of the zipfile to perform a manual update, also without success.
This all concerns a production site. I also have a local copy of the site to test updates before applying them in production. I also performed those tests this time and they worked fine. So I was a bit surprised to have "all" these production issues.
Therefor creating a ticket to get some help in solving this.
Cheers
Björn