aebe oryuga naseo dasi rogeu-inhaeyo.

Here, 에 marks the place or context where the error happens: in/on the app.

So 앱에 오류가 나다 means something like an error occurs in the app.

• 앱에 = in the app / on the app
• 오류가 나다 = an error occurs

You will often see 에 used this way with things like apps, websites, screens, systems, and documents when something exists or happens there.

Using 앱에서 would sound more like at/in the app as the location where an action is performed, but with 오류가 나다, 에 is the natural choice.

Literally, 나다 often means something like to come out, to appear, or to occur.

So 오류가 나다 is literally closer to an error comes up / occurs than to someone makes an error.

This is a very common Korean pattern:

• 문제가 나다 = a problem occurs
• 열이 나다 = a fever comes up / to have a fever
• 소리가 나다 = a sound is produced / a sound comes out
• 냄새가 나다 = a smell comes out / it smells

So 오류가 나서 means because an error occurred or since an error came up.

Because in 오류가 나다, the error is the subject of the verb 나다.

Korean is treating the situation as:

• The error occurred not
• Someone did an error

So:

• 오류가 나다 = an error occurs
• 오류를... would suggest 오류 is an object, which does not fit 나다

This is one of the places where Korean and English organize the idea differently. English often says the app has an error or there is an error, while Korean naturally says the error occurs.

나서 is 나다 + -아서/어서.

The ending -아서/어서 often connects two actions or clauses and usually means one of these:

1. because / since
2. and then

In this sentence, it is mainly giving a reason:

• 앱에 오류가 나서 다시 로그인해요.
• Because an error occurred in the app, I log in again.

So -나서 here is best understood as because it happened.

It can mean both, depending on context.

In this sentence, the most natural reading is cause:

• An error occurred, so I log in again.

But in other sentences, -아서/어서 can simply connect actions in order:

• 집에 가서 밥을 먹어요.
• I go home and then eat.

So the grammar itself can do both jobs. Context tells you whether it means because or and then.

로그인 comes from the English word login, but in Korean it is commonly turned into a verb with 하다:

• 로그인하다 = to log in

Then in the 해요 style:

• 로그인하다 → 로그인해요

This is very common with borrowed words and many nouns in Korean:

• 예약하다 → 예약해요 = make a reservation
• 체크하다 → 체크해요 = check
• 다운로드하다 → 다운로드해요 = download

So 로그인해요 simply means log in in polite everyday speech.

다시 means again, and it usually goes before the verb or verb phrase it modifies.

So:

• 다시 로그인해요 = log in again

That is the most natural placement here.

Korean adverbs like 다시, 잘, 빨리, 자주 often appear before the verb:

• 다시 해요 = do it again
• 빨리 가요 = go quickly
• 자주 먹어요 = eat often

Yes, -해요 is the present-form ending, but in Korean the present form often covers several English ideas depending on context:

• present habitual: I log in again
• present progressive-ish in context: I’m logging in again
• near future/intended action: I’ll log in again

So in this sentence, 다시 로그인해요 can naturally mean something like:

• I log in again
• I’m logging in again
• So I log in again

If you wanted to make it clearly past:

• 앱에 오류가 나서 다시 로그인했어요.
• An error occurred in the app, so I logged in again.

Korean often leaves out the subject when it is obvious from context.

So 다시 로그인해요 does not need 저는 if the listener already knows who is doing the action.

That is very normal in Korean. Adding 저는 is possible, but it can sound more explicit, contrastive, or topic-marking:

• 저는 앱에 오류가 나서 다시 로그인해요.

Without 저는, the sentence sounds more natural in many everyday situations.

Yes, that is possible, and it sounds natural.

There is a small nuance difference:

• 오류가 나서 = because an error occurred / came up
• 오류가 있어서 = because there is an error

So:

• 나서 focuses more on the error happening
• 있어서 focuses more on the error being there

Both can work, but 오류가 나서 is especially common when talking about technical problems suddenly appearing in an app, program, or device.

Not very well. A word-for-word breakdown helps with grammar, but natural English usually needs restructuring.

A close breakdown is:

• 앱에 = in the app
• 오류가 = an error
• 나서 = occurred / because it occurred
• 다시 = again
• 로그인해요 = log in

But natural English would usually be something like:

• There’s an error in the app, so I log in again.
• The app has an error, so I log in again.
• An error came up in the app, so I log in again.

This is a good example of how Korean often uses X가 나다 where English uses there is, have, or come up.