https://192.168.5.88/f5-w-687474703a2f2f31302e3133312e37312e31303a38303030
is
http://10.131.71.10:8000/ , so it's not SSL (between the "f5-w-" and "$$" is just hex encoded URL).
In the bottom of your screenshot, you have a Resource Item defined as http://10.131.71.10:8000/OA_HTML/ , but your aren't accessing that path with that rewrite URL, so if you have a Deny ACL, it could be denied by that ACL. Try using the http://10.131.71.10/* as the path instead for your resource item attached to that Portal Access list.
Also make sure the system can route to there. NOT the command line (control plane). It must be accessible via a TMM Route (data plane). An easy way to check is just make a LTM Pool to 10.131.71.10:8000 , put an HTTP monitor on it and make sure the pool status indicator turns green.
If both of those don't yield results, check the logs at /var/log/rewrite.log and also your browser's Network activity log (in dev tools in Chrome or FF).