I am working on extracting triplets from an annotated string, but the code's returning NULL. Here is the code used:-

library(tidyverse)
library(tm)
library(coreNLP)

# Increase Java heap space
options(java.parameters = "-Xmx4g")

# Initialize CoreNLP with the path to the unzipped folder
initCoreNLP("/Users/..../stanford-corenlp-4.5.7/")  

# Function to extract relations using CoreNLP
extract_relations <- function(text) {
  cat("Text to be annotated:\n", text, "\n\n")
  
  annotation <- tryCatch({
    annotateString(text)
  }, error = function(e) {
    message("Error in annotation: ", e)
    return(NULL)
  })
  
  if (is.null(annotation)) {
    message("Annotation is NULL")
    return(list())
  }
  
  print(annotation)
  
  triples <- tryCatch({
    getOpenIE(annotation)
  }, error = function(e) {
    message("Error in extracting OpenIE triples: ", e)
    return(NULL)
  })
  
  if (is.null(triples) || length(triples) == 0) {
    message("No triples extracted.")
    return(list())
  }
  
  print(triples)
  
}

# Mock dataset to train the model
mock_data <- data.frame(
  match_id = 1,
  home_team = "Manchester United",
  away_team = "Chelsea",
  match_preview = "Manchester United won their last game convincingly and have a strong home record. Chelsea, on the other hand, are struggling with injuries and have lost three of their last five away games.",
  outcome = "homewin",
  stringsAsFactors = FALSE
)

# Extracting features and assigning scores
match <- mock_data[1, ]
relations <- extract_relations(match$match_preview)

This is the output:-

Stanford core NLP used- stanford-corenlp-4.5.7
R version - R version 4.3.1
Is it an issue with the way CoreNLP is initialised or something else? Any help is appreciated.
Regards.