Check if your site is up. For this you can use a service like Down For Everyone or just for me. Maybe you have misspelled the url.
The Seobility bot has a connection timeout of 10 seconds, download timeout of 15 seconds and a maximum HTML download size of 5 MB. If your page exceeds one of this limits, it cannot be analysed.
Rarely the Seobility bot is blocked by a firewall. Please ensure that the Seobility bot can access your site.