Do you have the Movie Render Queue plugin enabled? We recently fixed an issue that will be coming out in 4.26.2 that caused the Automated Level Sequence Capture to not work if you have Movie Render Queue enabled. One possible workaround until 4.26.2 is released is to disable the Movie Render Queue plugin. Here’s the details of that issue:
Also, Automated Level Sequence Capture will eventually be deprecated as we’re putting all of the development efforts into Movie Render Queue. Here’s the documentation on that: