After updating Member plugin, I get error screen on member signup

Only after I upgraded to the latest version of the membership plugin did my new user subscriptions to the free plan (that allows members to see protected content -blog posts), did my users begin to get this page upon completion of the signup form:

Warning: Cannot modify header information - headers already sent by (output started at /home/content/06/9029706/html/wp-content/themes/canvas/header.php:22) in /home/content/06/9029706/html/wp-includes/pluggable.php on line 669

Warning: Cannot modify header information - headers already sent by (output started at /home/content/06/9029706/html/wp-content/themes/canvas/header.php:22) in /home/content/06/9029706/html/wp-includes/pluggable.php on line 670

Warning: Cannot modify header information - headers already sent by (output started at /home/content/06/9029706/html/wp-content/themes/canvas/header.php:22) in /home/content/06/9029706/html/wp-includes/pluggable.php on line 671

Warning: Cannot modify header information - headers already sent by (output started at /home/content/06/9029706/html/wp-content/themes/canvas/header.php:22) in /home/content/06/9029706/html/wp-includes/pluggable.php on line 866

-User info successfully makes it into wordpress as a user
-I went into advanced options. All tables ar "OK"
-I have no clue what's going on. It all happened after upgrading
-I had to reconfigure some settings, because it seems almost an overhaul of features were added.