Please, first of all enable debug mode using this instruction:
http://docs.oxwall.org/plugin-tuts:enable-debug.
Also, please, check the error.log if there are any errors: /ow_log/error.log file.
If you have found any errors and can't fix it than provide us the error messages so we could assist you.
If you've fixed it but there is still Blank page first of all, clear you browser cache.
In case it's doesn't help try to clear site cache by enabling DEV_MODE.
Follow the instructions
https://docs.oxwall.org/plugin-tuts:enable-debug
Or if there is still problem provide us an error logs.