Error while creating jira story

2021/05/11 16:41:09 ERROR: request failed. Please analyze the request body for more details. Status code: 400

panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x40 pc=0x1271f8d]

goroutine 1 [running]:
main.main()
/Users/Documents/jiratrial.go:44 +0x3ad
exit status 2

```
package main

import (
"fmt"
jira "github.com/andygrunwald/go-jira"
"log"
)

func main() {
base := "https://jira.com"
tp := jira.BasicAuthTransport{
Username: "",
Password: "",
}

jiraClient, err := jira.NewClient(tp.Client(), base)
if err != nil {
log.Println(err)
}

i := jira.Issue{
Fields: &jira.IssueFields{
Assignee: &jira.User{
AccountID: "",
},
Reporter: &jira.User{
AccountID: "",
},
Description: "Test Issue",
Type: jira.IssueType{
Name: "Story",
},
Project: jira.Project{
Key: "ABC",
},
Summary: "Just a demo issue",
},
}
issue, _, err := jiraClient.Issue.Create(&i)
if err != nil {
log.Println("ERROR: ", err)
}

fmt.Printf("%s: %+v\n", issue.Key, issue.Fields.Summary)
fmt.Println(issue)
}
```

getting an error while running this piece of code