IMAP imap too many simultaneous connections

Question

I am using imap-simple to access a mailbox. I have the following javascript code to read IMAP Mailbox.

    async getLastIncomingEmail() {
        //the imap config
        const imapEmailConfig = {
            imap: {
                user: existingEmail,
                password: existingPassword,
                host: 'imap.ethereal.email',
                port: 993,
                tls: true,
                authTimeout: 10000,
            }
        };
        flag = true
        i = 1

        while (flag) {
            try {
                //console.log(imapEmailConfig)
                const connection = await imaps.connect(imapEmailConfig)

                //  Open a mailbox, and look at the 50 newest messages
                await connection.openBox('INBOX')
                const searchCriteria = [
                    // "UNSEEN",
                    '1:50']
                const fetchOptions = {
                    bodies: [''],
                }
                delay(1000)
                console.log('delaying for 1 second')
                const messages = await connection.search(searchCriteria, fetchOptions)
                // and close the connection to avoid it hanging
                connection.end()

                if (!messages.length) {
                    console.log(`can not find new emails, nr of tries ${i}`)
                    i += 1
                    if (i === 90) {
                        flag = false
                        return null
                    }
                } else {
                    flag = false
                    console.log('there are %d messages', messages.length)

                    const mail = await simpleParser(
                        messages[messages.length - 1].parts[0].body,
                    )

                    /**
                     * It's possible to access these objects in the selected mail
                     * the following logs will be printed in Intellij Console to better understand the functionality
                     */

                    console.log(`Found following email : from ${mail.from.text}\n
                    from:${mail.to.text}\n
                    subject:${mail.subject}\n
                    date:${mail.date}\n
                    attachments:${mail.attachments}`)

                    return {
                        from: mail.from.text,
                        to: mail.to.text,
                        subject: mail.subject,
                        html: mail.html,
                        attachments: mail.attachments,
                        date: mail.date,

                    }
                }
            } catch (e) {
                console.error(e)
                return null
            }
        }

    }

the problem with the following code is that the connection is not closed. after running the test multiple times I get map too many simultaneous connections.

when I modify the code as follows

async getLastIncomingEmail() {
        //the imap config
        const imapEmailConfig = {
            imap: {
                user: existingEmail,
                password: existingPassword,
                host: 'imap.ethereal.email',
                port: 993,
                tls: true,
                authTimeout: 10000,
            }
        };
        flag = true
        i = 1
        //console.log(imapEmailConfig)
        const connection = await imaps.connect(imapEmailConfig)
        while (flag) {
            try {

                //  Open a mailbox, and look at the 50 newest messages
                await connection.openBox('INBOX')
                const searchCriteria = [
                    // "UNSEEN",
                    '1:50']
                const fetchOptions = {
                    bodies: [''],
                }
                delay(1000)
                console.log('delaying for 1 second')
                const messages = await connection.search(searchCriteria, fetchOptions)
                // and close the connection to avoid it hanging
                connection.end()

                if (!messages.length) {
                    console.log(`can not find new emails, nr of tries ${i}`)
                    i += 1
                    if (i === 90) {
                        flag = false
                        return null
                    }
                } else {
                    flag = false
                    console.log('there are %d messages', messages.length)

                    const mail = await simpleParser(
                        messages[messages.length - 1].parts[0].body,
                    )

                    /**
                     * It's possible to access these objects in the selected mail
                     * the following logs will be printed in Intellij Console to better understand the functionality
                     */

                    console.log(`Found following email : from ${mail.from.text}\n
                    from:${mail.to.text}\n
                    subject:${mail.subject}\n
                    date:${mail.date}\n
                    attachments:${mail.attachments}`)

                    return {
                        from: mail.from.text,
                        to: mail.to.text,
                        subject: mail.subject,
                        html: mail.html,
                        attachments: mail.attachments,
                        date: mail.date,

                    }
                }
            } catch (e) {
                console.error(e)
                return null
            }
        }

    }

no results will be fetched. How do I close the connection properly.