hacking core files is a VERY VERY bad idea (you will have the same problem every time wordpress updates)

there is no such thing as “Standard” style please refer to the shortcode documentation
https://docs.wp-pizza.com/shortcodes/

> if the client wants to pay for it.
sure. (building websites is not a charitable event after all :) )

PS: if you dont want to wait you can also send me your *test* merchant key and md5key (if any) (if you do, mark the reply as private here)

and the currency you are using

i don’t find this very legible (just my opinion)
however (not exactly the same but will make it somewhat more condensed), it force wraps at 74 characters
if you want it to wrap sooner ,you could set a couple of constants to be less

https://docs.wp-pizza.com/developers/?section=constants

notably
WPPIZZA_PLAINTEXT_MAX_LINE_LENGTH
and
WPPIZZA_PLAINTEXT_MAX_LINE_LENGTH_WORDWRAP

got a link ?

you could also try to disable the wppizza smtp functionality and see if you have more luck with another 3rd party smtp plugin

wppizza is of course not really a smtp plugin as such. i just added that option to perhaps be useful and i know it works on many/most servers (not to mention that i noticed that many smtp plugin store their smtp passwords in plaintext which – in my book – is far from ideal)

ok, that’s because you are using (I assume ?!) a gmail/googlemail, hotmail or yahoo address

none of these understand plaintext properly (not my fault – they used to , but not anymore. not the last time i checked anyway).
for instance plaintext is not displayed in those using monospaced fonts unless you jump through many hoops and it would ask too much of the average user to set this up. therefore plaintext email would look like a right old mess

therefore the plugin forces html with the “pre” tags to make this legible. you will find that not using a gmail/hotmail/yahoo address will give you proper plaintext

alternatively there is also a filter that checks for those email addresses you could use to unset this behaviour for gmail
like so

/* not tested as such but should work */
add_filter('wppizza_email_plaintext_to_webmail_domains', 'my_filter');
function my_filter($email_domains){
unset($email_domains[0]);//where 0 = @gmail. | 1 = @googlemail. | 2 = @outlook | 3 = @yahoo.| 4 =@hotmail.
return $email_domains
}

but if you send plaintext emails to customers that have gmail accounts and use that filter, they would get the same mess

did you “verify that the domain or address is defined for this server.”
test smtp emails simply use the default wp_mail from address (something like [email protected])
whereas “live” emails so to speak use the settings in wppizza->settings ->emails

i guess i should probably change this to be used for test emails too at some point.
as it is what it is at the moment, have you tried doing a test email with an actual test order ?

PS: when you test it, it does not even use any saved parameters but directly what you have typed into the formfields

have you used/run the test there (i assume we are talking about the smtp settings section in the wppizza plugin) ?
what does the output give you ?