"Error: lexical error: invalid char in json text. " when using Purrr loop in R

Question

Kinda long winded but here goes:

I have a dataframe like this:

testprotocols<-structure(list(protocol_no = c("LS-P-Joe's API", "JoeTest3"), 
    nct_number = c(654321, 543210), library = structure(c(2L,
    2L), levels = c("General Research", "Oncology"), class = "factor"),
    organizational_unit = structure(c(1L, 1L), levels = c("Lifespan Cancer Institute", 
    "General Research"), class = "factor"), title = c("Testing to see if basic stuff came through",
    "Testing Oncology Projects for API"), department = structure(c(2L,
    2L), levels = c("Diagnostic Imaging", "Lifespan Cancer Institute"
    ), class = "factor"), protocol_type = structure(2:1, levels = c("Basic Science",
    "Other"), class = "factor"), protocolid = 1:2), row.names = c(NA,
-2L), class = c("tbl_df", "tbl", "data.frame"))

I want to push it into a website using an API with this code, that'll go line by line and return a dataframe given me the status of whether or not that row worked:

##This chunk gets a random one we're going to change later
base <- "https://website.forteresearchapps.com"
endpoint <- "/website/rest/protocols/"
protocol <- "2501"

## 'results' will get changed later to plug back in


## store
protocolid <- protocolnb <- library_names <- get_codes <- put_codes <- list()

UpdateAccountNumbers <- function(protocol){
  call2<-paste(base,endpoint, protocol, sep="")   
httpResponse <- GET(call2, add_headers(authorization = token))
results = fromJSON(content(httpResponse, "text"))


results$protocolId<- "8887"  ## doesn't seem to matter
results$protocolNo<- testprotocols$protocol_no
results$library<- as.character(testprotocols$library)
results$title<- testprotocols$title
results$nctNo<-testprotocols$nct_number
results$objectives<-"To see if the API works, specifically if you can write over a previous number"
results$shortTitle<- "Short joseph Title"
results$nctNo<-testprotocols$nct_number
results$department <- as.character(testprotocols$department)
results$organizationalUnit<- as.charater(testprotocols$organizational_unit)
results$protocolType<- as.character(testprotocols$protocol_type)

  call2 <- paste(base,endpoint, protocol, sep="") 

  httpResponse_put <- PUT(
    call2, 
    add_headers(authorization = token), 
    body=results, encode = "json", 
    verbose()
  )

  # save stats 
  protocolid <- append(protocolid, protocol)
  protocolnb <- append(protocolnb, testprotocols$PROTOCOL_NO[match(protocol, testprotocols$PROTOCOL_ID)])
  library_names <- append(library_names, testprotocols$LIBRARY[match(protocol, testprotocols$PROTOCOL_ID)])
  get_codes <- append(get_codes, status_code(httpResponse_get))
  put_codes <- append(put_codes, status_code(httpResponse_put))
}
## Oncology will have to change to whatever the df name is, above and below this
purrr::walk(testprotocols$protocol_no, UpdateAccountNumbers)

allresults <- tibble('protocolNo'=unlist(protocol_no),'protocolnb'=unlist(protocolnb),'library_names'=unlist(library_names), 'get_codes'=unlist(get_codes), 'put_codes'=unlist(put_codes) )

This basic gist of purrr loop is from my question here: Question

The only difference is that in that question, I was only doing one small change within the loop, this line:

results$hospitalAccountNo <- results$internalAccountNo

Where it would take what it downloaded from the API, copy it over to 'hospitalAccountNo' and put it back up.

This time around, I'm trying to make a few more changes: all of these lines which I envision using the 'testprotocols' dataframe and writing over the 'results' it downloaded, then uploading one row at a time using the loop.

results$protocolId<- "8887"  ## doesn't seem to matter
results$protocolNo<- testprotocols$protocol_no
results$library<- as.character(testprotocols$library)
results$title<- testprotocols$title
results$nctNo<-testprotocols$nct_number
results$objectives<-"To see if the API works, specifically if you can write over a previous number"
results$shortTitle<- "Short joseph Title"
results$nctNo<-testprotocols$nct_number
results$department <- as.character(testprotocols$department)
results$organizationalUnit<- as.charater(testprotocols$organizational_unit)
results$protocolType<- as.character(testprotocols$protocol_type)

For whatever reason, when I try to run the line:

purrr::walk(testprotocols$protocol_no, UpdateAccountNumbers)

If I run traceback() I get this:

I'd love it if someone could just fix my entire loop for me haha, but realistically my question is:

Where should I look to figure out what is causing this error?