POSIXlt object showing NA values after conversion

Question

I am trying to add ride length calculation to all_trips data frame in seconds. To do that I have to use difftime() function and also convert start_time and end_time colunms to POSIXlt objects before calculating the time difference.

During my conversion of start_time and end_time columns to POSIXlt objects I get NA values as the POSIXlt format

This is what I tried:

all_trips$start_time <- as.POSIXlt(all_trips$start_time, format = "%m/%d/%Y %H:%M", tz = "UTC")
all_trips$end_time <- as.POSIXlt(all_trips$end_time, format = "%m/%d/%Y %H:%M", tz = "UTC")

My expectation:

start_time: POSIXlt, format: "2023-01-01 12:00:00" "2023-01-02 13:00:00" ...
end_time  : POSIXlt, format: "2023-01-01 12:30:00" "2023-01-02 13:30:00" ...

My actual result:

start_time: POSIXlt[1:5723606], format: NA NA NA ...
end_time  : POSIXlt[1:5723606], format: NA NA NA ...

My data:

  trip_id          bikeid        start_time   end_t…¹ from_…² from_…³ to_st…⁴ to_st…⁵ user_…⁶
  <chr>            <chr>         <chr>        <chr>   <chr>   <chr>   <chr>   <chr>   <chr>  
1 9340B064F0AEE130 electric_bike 7/23/2023 2… 7/23/2… Kedzie… 20204   Public… 877     member 
2 D1460EE3CE0D8AF8 classic_bike  7/23/2023 1… 7/23/2… Wester… KA1504… Milwau… 13033   member 
3 DF41BE31B895A25E classic_bike  7/23/2023 1… 7/23/2… Wester… KA1504… Damen … TA1305… member 
4 9624A293749EF703 electric_bike 7/21/2023 8… 7/21/2… Racine… 13155   Clinto… TA1305… member 
5 2F68A6A4CDB4C99A classic_bike  7/8/2023 15… 7/8/20… Clark … TA1309… Montro… TA1308… member 
6 9AEE973E6B941A9C classic_bike  7/10/2023 8… 7/10/2… Racine… 13155   Sangam… TA1306… member