Nakon preusmjeravanja sve je prošlo fino.

Because nakon takes the genitive case.

The base form is preusmjeravanje. After nakon, it changes to preusmjeravanja.

• preusmjeravanje = redirecting / rerouting / forwarding
• nakon preusmjeravanja = after the redirecting / after the rerouting

So this is a normal case change required by the preposition.

It is a verbal noun built from the verb preusmjeriti / preusmjeravati.

It refers to the action or process of:

• redirecting
• rerouting
• forwarding

The exact English translation depends on context. For example, it could be about:

• phone calls
• internet traffic
• mail
• users being sent to another page
• technical routing of some kind

So it is not a finite verb here; it is a noun naming an action.

Because sve here means everything, and in Croatian that is treated as grammatically singular neuter.

That is why you get:

• sve = everything
• je = singular auxiliary
• prošlo = neuter singular past participle

So even though everything feels semantically broad, grammatically it behaves like a singular neuter subject.

Literally, yes: it comes from proći, which often means to pass or to go through.

But in this sentence, prošlo je is used idiomatically. It means something like:

• went
• turned out
• went through successfully
• happened without problems

So sve je prošlo fino is not about physically passing by; it means everything went fine.

Je is the auxiliary verb to be, used to form the perfect tense in Croatian.

The structure is:

• je
  • prošlo

That corresponds to English has gone / went, depending on how naturally you translate it.

So:

• sve je prošlo = everything went / everything has gone

In standard Croatian, this auxiliary is part of the normal past-tense form.

Here it is an adverb.

It describes how everything went:

• fino = nicely / fine / smoothly / well

It does not describe a noun here, so it is not acting as an adjective.

In everyday Croatian, fino is quite common and often sounds a bit:

• conversational
• friendly
• mildly informal

It often means more than a direct word-for-word fine.

In this sentence, fino suggests that things went:

• smoothly
• nicely
• without trouble
• in a satisfactory way

Compared with dobro, fino can sound a little softer or more colloquial.

So:

• Sve je prošlo dobro. = Everything went well.
• Sve je prošlo fino. = Everything went fine / smoothly.

Both are natural, but fino has a slightly different tone.

Yes, absolutely.

• Sve je prošlo dobro. = very standard, neutral
• Sve je prošlo fino. = natural, a bit more conversational or warm

Depending on context, you might also hear:

• Sve je prošlo u redu. = Everything went okay / all right
• Sve je prošlo bez problema. = Everything went without problems
• Sve je prošlo glatko. = Everything went smoothly

So fino is natural, but not the only option.

It is placed first to set the time/context right away: after the redirecting/rerouting.

Croatian word order is fairly flexible, so other versions are possible, for example:

• Sve je nakon preusmjeravanja prošlo fino.
• Sve je prošlo fino nakon preusmjeravanja.

These all mean roughly the same thing, but the emphasis changes a little.

Starting with Nakon preusmjeravanja highlights the circumstance first, which is very natural in Croatian.

Yes, in many contexts you could say:

• Poslije preusmjeravanja sve je prošlo fino.

That would also mean After the rerouting/redirecting, everything went fine.

Both nakon and poslije are common. Very broadly speaking:

• nakon can sound a bit more neutral or standard
• poslije is also common and natural in everyday speech

Both take the genitive in this use.

Overall, it is mostly neutral, but fino adds a slightly colloquial tone.

So the sentence would fit well in:

• conversation
• informal reporting
• everyday written communication
• technical discussion with a casual tone

If you wanted a more formal or technical style, you might choose something like:

• Nakon preusmjeravanja sve je prošlo dobro.
• Nakon preusmjeravanja sve je proteklo uredno.
• Nakon preusmjeravanja nije bilo problema.

But the original sentence is perfectly natural and idiomatic.