Unable to send mail from my iPhone

I'm sorry to hear that you're having trouble sending email from your iPhone. There could be a few different reasons for this, such as if you have an issue with your email account settings or if there is a problem with your Internet connection. Here are a few things you can try to troubleshoot the problem:

1. Check your Internet connection: Make sure that your iPhone is connected to the Internet. If you're using WiFi, try turning it off and using cellular data instead, or vice versa.
2. Check your email account settings: Make sure that your email account is set up correctly on your iPhone. To check your account settings, go to the Settings app, tap "Passwords & Accounts," and then tap on your email account. Make sure that the account information is correct and that the "Outgoing Mail Server" settings are set up correctly.
3. Restart your iPhone: Sometimes, simply restarting your device can resolve issues like this. To restart your iPhone, press and hold the power button until you see the "slide to power off" slider. Then, slide the power off slider to the right to turn off your iPhone. Once your iPhone is off, press and hold the power button again to turn it back on.
4. Check for a software update: Make sure that your iPhone is running the latest version of iOS. You can check for updates by going to the Settings app, tapping "General," and then tapping "Software Update."

I hope one of these steps helps resolve the issue you're experiencing. If you have any other questions, please don't hesitate to ask.