Receiving reported error (0x8004210E):

Hi Umrk,

For us to better know your concern, we'd like to asks ome information.

- Which email provider are you using on your iPhone 7?

- Are you using Outlook 2013 on your iPhone 7 or on your computer?

- Are you getting the error message on your computer or on your iPhone 7?

Kindly provide us a detailed information of your concern so that we can provide the appropriate resolution.

Hope to hear from you soon.

Thank you for your reply. To be concise, my responses to your questions are detailed below:

1. Emails are downloaded from Spectrum/TWC's server

2. The default email program included in apple's iPhone OS is used to read/reply/send email

3. The iPhone's emails settings were entered per Spectrum/TWCs spec.

4. Outlook 2013 runs on my PC running Win 7 Ultimate x64

5. The error message quoted in my OP was displayed on my pc by Outlook 2013.

6. iPhone does not generate error messages relating to this issue, in fact, there is no problem with emails on the iPhone. The problem is with Outlook 2013 on my PC.

Finally, this issue seems to be with my PC's inability to access the server to send or receive emails because the iPhone is blocking access to the Spectrum/TWC server, despite the iPhone being powered down. This happens every time the iPhone is used to read/reply/send email. As a reminder, the Outlook 2013 error message reads:

‘Receiving reported error (0x8004210E): 'Your mailbox is temporarily unavailable because another e-mail message is being delivered to it or another mail application is accessing it.  The server responded: -ERR [IN-USE] account is locked by another session or for maintenance, try again.'

Thank you in advance,

Umrk

Do you have an Anti-Virus/Security software installed on your computer?

If yes, try disabling the incoming and outgoing email scan feature on the Anti-Virus/Security Software and check if it helps to resolve
this issue.

Keep us updated with your concern.

Kindly try the suggested troubleshooting steps on the article below.

Outlook not responding, stuck at "Processing,"stopped working, freezes, or hangs

Let us know if you need further assistance.

- Which email provider are you using on your iPhone 7?

The iPhone accesses emails using the TWC/Sprectum server - roadrunner.  The phone also utilizes Apple's iCloud server.

- Are you using Outlook 2013 on your iPhone 7 or on your computer?

No

- Are you getting the error message on your computer or on your iPhone 7?