Please send your email to trailhead at "trailhead@salesforce.com" or submit your feedback from below screen on right side bottom on trailhead page
Where can I suggest a new feature or share general feedback? We’d love to hear from you! Use the “Share Feedback” button in the footer or on the right column to send feature requests or other comments.
Myself also faced this issue past in chrome, After I did update my browser to latest version and reduced few of the chrome extensions(which are causing delay in loading the web pages) The issue seems to be resolved for me.
Where can I suggest a new feature or share general feedback?
We’d love to hear from you! Use the “Share Feedback” button in the footer or on the right column to send feature requests or other comments.
1) https://developer.salesforce.com/page/Trailhead_FAQ
Myself also faced this issue past in chrome,
After I did update my browser to latest version and reduced few of the chrome extensions(which are causing delay in loading the web pages)
The issue seems to be resolved for me.
Thanks,
Hari Kundrapu