When I try to add form to maineniche.com/login the following messge appears:
Warning: Cannot modify header information - headers already sent by (output started at /home/mainnic/public_html/wp-content/plugins/accesspress-anonymous-post-pro/accesspress-anonymous-post-pro.php:1565) in /home/mainnic/public_html/wp-includes/pluggable.php on line 1216
I placed the login page in the trash and unable to restore? I seemed to have messed things up? 
Any suggestions? Please note that I don’t do coding or back-end fixes. Thanking you in advance for your help.