It is not wrong, this is just highly ambiguous. If it is meant to say "I will have" in an ordering context you wouldn't use the verb avere (to have), you would use prendere (to take). For example "prendo un gelato al caffè" (I take a coffee ice cream) or "voglio prendere un gelato al cafè" (I want to take a coffee ice cream). The verb to have (avere) is not used in these contexts as it is in english. It thus depends on whether this sentence was intended to be a statement "ho un gelato al caffè" (I have a coffee ice cream) or a request "ho il gelato al caffè" (I have the coffee ice cream), but the second is just wrong and you would not use it in any context (source: my fiancé is Italian, native speaker). On a side note... "ho un gelato al caffè" can also mean "I have an ice cream at the cafè", while technically correct, is not used anymore, so just watch out for that. Also, I noticed that most people are using "io" and I just wanted you let you all know that it is not necessary and not used in spoken Italian (just like tu, lui/lei, voi, noi and loro). You can just use the conjugated verb (eg. ho, hai, ha, avete, abbiamo, hanno). I hope this helps!

Because it is "I have coffee ice cream", not "I have an ice cream at the cafe".

your translation is "I have A coffee ice cream". Why Duo wanted il and un was not accepted is not clear. Perhaps someone could clarify. What's the diff?

It means i have a coffee ice cream

When you say "un gelato" it means "an ice cream." When you say "il gelato" it means either "ice cream" or "the ice cream."

moo

I have one coffe ice cream .. It should be the not one

You said "un" instead of "il"

Because it is the ice cream, not a ice cream, therefore it would be Ho il gelato al caffè

You would say "prendo un affogato al caffè", yeah? Because affogato is a type of gelato, caffè is the flavour?

Because you just said that you have ice cream flavored coffee when really you have coffee flavored ice cream. Therefore it would be Ho il gelato al caffè

"ho" is conjugated from the verb "to have: avere".

And, unlike in English, a verb gives out quite a lot of information. Just by looking at it you'll know who the text speaks of - "ho" tells that it's YOU (as in first person singular), so you don't need to type out "io".

simple chart: -http://iltavoloitaliano.com/learning_avere_present_tense/

"al" in this case can be treated as "with", like "made with". It works the same way in French. In English, you're used to prepositions having set meanings, in Romance languages like Italian and French, that's not the case. The meanings cover multiple things that we express differently in English. It's something you will have to get used to when learning a new language. Throw away your English mind.

why is chocolate ice cream said crema al cioccolato & coffee ice cream is gelato al caffe?

On my samsung I hold my finger on the e button and it pulls up all options for the letter, è, é, ê, ë