working on a practice modal and keep getting an error. checked on my local machine with identical code it works.

You're definitely using the correct code to make a string! But look at the question again:

"create a new variable named email_greeting that puts the treehouse variable and the name variable into the sentence "X loves Y" but with treehouse for X and name for Y."

Are your treehouse and name variables in the right place?

I recommend using the print() command when using "local machines" For example:

name = "Ernest"
treehouse = ("Tree"+"house")
email_greeting = (name +" loves " + treehouse)
print (email_greeting)

That way it will show you what the "test environment" will be getting as its answer and you can check it against the question. (I do this often when I'm stuck with this kind of challenge)

As for your code it has the, you night want to swap "name" and "treehouse" around in this line of code:

email_greeting = (name +" loves " + treehouse)

PS: If using print() in "local machines" you might also want to use "import time" at the start and "time.sleep(5)" ("(5)" makes it wait 5 secs, can be replaced with (10) to make it last longer.) after print() so you have enough time to read the printed awnser before the program closes.

import time #put up with other imports
time.sleep(5) #put after the "print()" command 

PSS: I only know that amount about the "import time" and "time.sleep(5)" as i only found out how to use it to delay my programs from closing.