Limits are starting to be applied for totally free full-site and single-URL tests.
At present there are limits on the number of full-site tests you can run per website per month. Similarly there are limits on the number of single-URL tests you can run per URL per month.
These apply only if you have not signed in.
Full-site tests are limited to 10 per website per month:
Single-URL tests are limited to 10 per URL per month:
The above limit of 10 is not set in stone and is likely to vary over the next few weeks.
You will need to create an account or sign in to run further tests.