Check mail queue

To check the mail queue, you can use the following commands:

For Linux and macOS:

mailq: This command displays the current mail queue, showing the sender, recipient, and status of each message.
```
mailq
```
postqueue -p: This command shows the current mail queue, including the sender, recipient, and status of each message.
```
postqueue -p
```
For Windows:
msmq: This command displays the current mail queue, showing the sender, recipient, and status of each message.
```
msmq
```
postqueue -p: This command shows the current mail queue, including the sender, recipient, and status of each message.
```
postqueue -p
```
For Exchange Server:
Get-MailQueue: This PowerShell cmdlet displays the current mail queue, showing the sender, recipient, and status of each message.
```
Get-MailQueue
```
Get-Message: This PowerShell cmdlet shows the current mail queue, including the sender, recipient, and status of each message.
```
Get-Message -Status
```
For Postfix:
postqueue -p: This command shows the current mail queue, including the sender, recipient, and status of each message.
```
postqueue -p
```
mailq: This command displays the current mail queue, showing the sender, recipient, and status of each message.
```
mailq
```
Note: The exact command and syntax may vary depending on your mail server software and configuration.