testing php mail function

I have installed sendmail and trying to use a basic mail function in a php page that works on another server.

Have tried a few command line test emails that both worked fine. Successful tests:

that worked, then I tried...

echo "this is email body"|mail -s "This is email subject" peter@myemail.com

which also worked fine

However, the PHP mail function is dead. The only thing I’ve come across that seemed odd were some error message during the sendmail install process:

Creating /etc/mail/sendmail.cf...
*** ERROR: FEATURE() should be before MAILER()
*** MAILER(`local') must appear after FEATURE(`always_add_domain')*** ERROR: FEATURE() should be before MAILER()
*** MAILER(`local') must appear after FEATURE(`allmasquerade')*** ERROR: FEATURE() should be before MAILER()
 
Creating /etc/mail/submit.cf...
Informational: confCR_FILE file empty: /etc/mail/relay-domains
Informational: confCT_FILE file empty: /etc/mail/trusted-users
Updating /etc/mail/access...
Updating /etc/mail/aliases...
/etc/mail/aliases: 1 aliases, longest 4 bytes, 14 bytes total
 
Warning: These messages were issued while creating sendmail.cf
	make sure they are benign before starting sendmail!
 
Errors in generating sendmail.cf
*** ERROR: FEATURE() should be before MAILER()
*** MAILER(`local') must appear after FEATURE(`always_add_domain')*** ERROR: FEATURE() should be before MAILER()
*** MAILER(`local') must appear after FEATURE(`allmasquerade')*** ERROR: FEATURE() should be before MAILER()

Any ideas? I’ve googled ‘test php mail function’ and read through numerous posts but nothing seemed to work or fit with my context… Ubuntu 14/Nginx/PHP.