Theme does not show, new site admin has redirect loop

Hi there,
After being locked out of my main admin following a multisite install on an existing WP site at GoDaddy, I have disabled all plugins and am running my site in debug mode. This is a revelation as many plugins were causing sundry errors. I began deleting the disabled plugins until the errors went away one at a time their paths were displayed so easy to identify the offending plugin)…

BUT all that’s happened now is that the new site is created; it’s not shown in the drop down list even though it’s shown via the “All Sites” link, and the homepage and other pages of the site don’t display the default or any theme. (As matter of fact, when I change the default theme from the network admin the twentythirteen theme remains the default.)

When I attempt to log in to the new site admin via another browser, I’m told that “This webpage has a redirect loop”.

When I view the homepage source all the links are there for the template, scripts, rss feeds etc and they work eg https://www.abengnews.com/syndicate/feed/ which means the basic URL redirect works.

How do I get the theme to display on the created site and find what’s causing the redirect loop to wp-login.php?

Thanks for your help.