The most common complaint about Google Search Analytics is that the profiler gets stuck when trying to access the data.
It looks like this:
And it just remains, 'Fetching Data' like this, forever.
This is caused by the way that the API handles verified domains; which means that an unverified domain will still appear in your dropdown list of domains to choose from in the options.
You can check if you are verified for a domain by logging into Google Search Console:
If you see this, you will need to click 'Verify this property' on the right, and follow through with the domain owner to make sure you get verified.
Another typical issue is that the data comes back as all 0s:
Unless you have an extremely unpopular site(!), this is unlikely to be accurate.
Typically this is caused by the wrong domain being selected from the dropdown. As URL Profiler will actually be autorised for the domain you have selected, when it goes to get the data it will not find anything that matches as the URLs will be different.
The important thing to remember in this case is that each different site or subdomain version needs to be verified in Google Search Console: