Here are some tips to help you troubleshoot trained journeys:
"Tried to click, but timed out waiting for..."
"Tried to click, but could not find the..."
Confirm that the element still exists.
Confirm that you were not logged in to the application under test and that your cookies for the domain under test were cleared before journey training.
Does your journey include actions that fire on a mouse hover? If so, create a new journey and ensure that "Capture hovers" is enabled prior to any step that includes a hover.
"An unknown error occurred during the execution of a test operation"
"Failure attempting to load page"
Confirm that the target URL for the plan and journey are accessible from the public internet.
Confirm that the specific page listed above the error message is accessible via the public internet.
Confirm the SSL certificates are not expired, match the visited domain, and are signed by a trusted CA.