When selecting an installation location on the install screen, "We didn't find any Salesforce accounts linked to your Trailblazer.me profile. To create an account, sign up for a free trial of Salesforce." is displayed. My Salesforce account is already connected to Trailblazer.
This may be a connection issue between your Salesforce account and Trailblazer. Contact Salesforce Help.
When accessing the AppExchange, the "503 first byte timeout" error message shows.
It is due to a Salesforce Known Issue. Refresh the page or try again later. If access is still not available after 2-3 hours, contact Salesforce Help.
Salesforce Known Issues
'Error 503 first byte timeout' sometimes displayed when accessing an AppExchange listing