In case you use In moodle 3.3 with social login:
Add to Randy's solution:
In /auth/oauth2/confirm-account.php
Change lines into:
51 echo $OUTPUT->single_button("$CFG->wwwroot/my/", get_string('myhome'));
87 echo $OUTPUT->single_button("$CFG->wwwroot/my/", get_string('myhome'))
It's a pity that this must be done in the core code, but it works.
Don't forget to empty the cache