[@fionalai708 Participant 6 years, 6 months ago]

I deactivate all plugins except for bbpress, test to register but failed still.

set up email to come from my site eg @mysite.com and
contact my host provider (SG) to help – problem still.

I install  https://wordpress.org/plugins/check-email/  
admin accepted test email.
but problem still too.now I deactivate plugin check-email.

SG help me to set plugin”WP Mail SMTP” .problem still too.

hope can assist me. thanks a lot.