Can create an .ics file, but it doesn't do anything

[kezzer]

I have a df of this pattern:

structure(list(`DTEND;VALUE=DATE` = structure(c(19389, 19395, 
19396, 19402, 19409, 19410), class = "Date"), `DTSTART;VALUE=DATE` = structure(c(19389, 
19395, 19396, 19402, 19409, 19410), class = "Date"), SUMMARY = c("Activity", 
"Activity", "Activity", 
"Activity", "Activity", 
"Activity"), UID = c("beb9cbab6d0a2534d17c", 
"0f57d3b22bd2b6ed4950", "c3f192b290e8f001529c", "c15769cc203dfbe8caa6", 
"d3554e447336aa78ddd8", "e78a4cfd97307bdb2ea5"), SEQUENCE = c("0", 
"0", "0", "0", "0", "0"), DTSTAMP = c("20230116T175008Z", "20230116T175008Z", 
"20230116T175008Z", "20230116T175008Z", "20230116T175008Z", "20230116T175008Z"
), DESCRIPTION = c("link to open", 
"to open", 
"link to open", 
"link to open", 
"link to open", 
"link to open"
), LOCATION = c("M", "M", "M", 
"M", "M", "M"
)), row.names = c(NA, -6L), class = c("tbl_df", "tbl", "data.frame"
))

I'm attempting to use the library(calendar) to convert this dataframe to a usable ics format. While the following produces a ics file on my computer, it doesn't do anything while trying to export it to outlook (or open it directly):

ic_write(df, MY-DESKTOP-LOCATION)

Using the guidance found here: calendar package - RDocumentation
Downloading the example file (found at the top of the page), converting it to another df using the function: ic_read() and then using the ic_write() again does work for that example file.
Does anyone know why my df (dput above) is not functioning as expected? (Events posted are meant to be all-day events).