Sentí frustración cuando el wifi falló justo antes de la videollamada.

Both are correct, but they are built differently:

• Sentí frustración = I felt frustration

  • Here, frustración is a noun.
  • The verb is sentir
    • a thing you feel.

• Me sentí frustrado/a = I felt frustrated

  • Here, frustrado/a is an adjective.
  • The verb is sentirse
    • an adjective describing your state.

So the sentence uses the noun pattern:

• sentir + frustración
• similar to sentir miedo, sentir alegría, sentir rabia

If the speaker is male, they could also say Me sentí frustrado. If female, Me sentí frustrada.

Sentí is the preterite of sentir: I felt.

It is used because the sentence refers to a feeling connected to a specific completed moment in the past:

• the wifi failed
• right before the video call
• at that moment, the speaker felt frustration

The preterite is very common for events or reactions seen as complete:

• Sentí alivio
• Sentí miedo
• Sentí frustración

If you wanted to describe an ongoing emotional state in the past, you might use the imperfect in another context, but here the sentence focuses on the moment the feeling happened.

Spanish often leaves out subject pronouns because the verb ending already shows who the subject is.

• Sentí clearly means I felt
• so yo is not necessary

You could say Yo sentí frustración, but that usually adds emphasis, contrast, or clarification.

For example:

• Yo sentí frustración, pero ella se lo tomó con calma.

In a normal sentence, leaving out yo sounds natural.

Here, fallar means something like:

• to fail
• to stop working properly
• to let someone down in some contexts

So el wifi falló means:

• the wifi failed
• the wifi stopped working
• the wifi malfunctioned

Falló is the preterite form, because it refers to a specific event in the past.

You could also hear similar verbs in related situations:

• se fue el internet = the internet went out
• se cayó la conexión = the connection dropped
• no funcionaba el wifi = the wifi wasn’t working

But falló is a perfectly natural choice.

The accent mark shows the correct stress and also helps identify the verb form.

• fallo = I fail or a failure / a fault
• falló = he/she/it failed

So:

• yo fallo
• el wifi falló

The accent tells you the stress is on the last syllable in this past-tense form:

• fa-LLÓ

This is very common in the preterite:

• habló
• comió
• vivió
• falló

In Spain, wifi is very commonly used as a masculine noun:

• el wifi

So el wifi falló is completely natural.

You may also hear variation in real life, and some speakers do use la wifi, but el wifi is very common and widely accepted in everyday Spanish in Spain.

Learners should be comfortable with:

• el wifi va mal
• el wifi no funciona
• el wifi falló

Justo antes de means right before.

It adds emphasis: not just before, but immediately before or at the worst possible moment.

Compare:

• antes de la videollamada = before the video call
• justo antes de la videollamada = right before the video call

That justo makes the timing feel especially frustrating.

You can use this pattern a lot:

• justo antes de salir
• justo antes del examen
• justo antes de empezar

Because antes normally needs de before a noun or infinitive.

So you say:

• antes de la videollamada
• antes de salir
• antes de comer

Not:

• antes la videollamada

This is a fixed structure you should memorise:

• antes de + noun
• antes de + infinitive

La videollamada refers to a specific video call, the one that was about to happen.

Spanish often uses the definite article more than English does. In English, we might say:

• right before the video call
• or sometimes just right before a video call, depending on context

In Spanish, if both speaker and listener know which call is meant, la videollamada sounds natural:

• justo antes de la videollamada

Also, videollamada is feminine, so it takes:

• la videollamada

Yes. Videollamada is a normal and common word in Spain for video call.

It is formed from:

• video
• llamada = call

So literally, it is a video call.

You may also hear:

• hacer una videollamada = to make a video call
• tener una videollamada = to have a video call

In everyday speech, some people may also mention the platform instead:

• tenía una llamada por Zoom
• tenía una reunión por Meet

But videollamada is absolutely standard.

Yes, you could, and it would sound natural.

Compare:

• Sentí frustración cuando el wifi falló...

  • slightly more descriptive
  • focuses on the emotion as a thing felt

• Me frustré cuando el wifi falló...

  • more direct
  • means I got frustrated

Both work well. The difference is mostly about style and focus.

Other natural options include:

• Me sentí frustrado/a cuando el wifi falló...
• Me dio mucha frustración cuando el wifi falló...
  
  • less neutral, more colloquial in some contexts

The word order in the sentence is very natural:

• Sentí frustración = main reaction
• cuando el wifi falló = when the triggering event happened
• justo antes de la videollamada = extra time detail

Spanish word order is fairly flexible, but this version sounds clear and standard.

You could also say:

• Cuando el wifi falló justo antes de la videollamada, sentí frustración.

That version puts the event first and the emotional reaction second. Both are correct.

The original sentence is nice because it starts with the speaker’s feeling, which gives it a strong emotional focus.