Outlook 2007 receives emails but won't send over wifi. Multiple email

Not sure if this has to the latest Win10 2004 update a few days ago or not.

I have been using MS Outlook for many years with Cox.net and have no problems getting email from the cox mail server to Outlook. I have not changed any ports or anything else.
All works fine on my home wifi with Outlook and Cox.net

The same thing happens with my cell phones while on the same wifi. Can get all incoming email but unable to send and get error message that it couldn't authenticate.

Now when I turn off wifi and use my T-Mobile site everything works great. Emails come in and goes out.

Now I'm not at home but at a campground that I'm using. Can they block cox.net incoming mail some how?

Not a super hot problem but was wondering if it can be something on my computer end.

Here is the error message I get in Outlook when it fails to send email.

Cox says all works good on their site so its not their issue with 3rd party software settings. LOL

Any ideas or suggestion?
Thanks

- - - Updated - - -

Weird. I still think its the campground wifi network is the issue.
Anyone else agree?

Search your error message. Cloudmark looks like a filter system and likely has the campground IP address listed as a spammer and so it is being blocked by Cox. (and everyone else using this service)

You could get the IP address, whatismyip.com, (this is campsite's public facing IP address) and then see how you would get Cox to remove from Blacklist.


A simpler solution, assuming you have a reasonable data plan, connect your laptop to your cell phone hotspot when you use Outlook. Your IP will be clean.


Ken

Yes all your ideas are feasible and still working on it.
Hotspot is my alternative or just log into COX email and use their mail software online.
Will keep you posted.

Yes but I was saying use outlook on your laptop with your laptop connected to phone wifi. (hotspot)

Caledon Ken said:

Yes but I was saying use outlook on your laptop with your laptop connected to phone wifi. (hotspot)

Got it. Thanks

I think you are saying
- EMail client - MS Office Outlook 2007
- EMail ISP - Cox.Net
and that the normal behaviours are
- computer connected to home network - Outlook 2007 can send & receive EMail
- phone using its mobile/cellular data connection - phone's email app can send & receive EMail
- computer connected to phone using its mobile/cellular data connection - Outlook 2007 can send & receive EMail
but
- computer connected to campsite network - Outlook 2007 can receive EMail but not send EMail
- phone connected to campsite network - ???????

I once had this problem with a hotel WiFi - Outlook 2007, EMail ISP - Outlook.com.
I changed my EMail settings in Outlook 2007 and the problem was fixed.
I knew that the recommended settings had changed months before but, since EMail was normally working alright I had not bothered changing my settings.

You'll find your settings in
Outlook 2007,
Tools,
Account settings,
<email account>,
Change...,

!Check the settings in that dialog against Cox.Net recommended settings!,

More settings ...,
Outgoing server tab,

!Check the settings in that dialog against Cox.Net recommended settings!,

Advanced tab,

!Check the settings in that dialog against Cox.Net recommended settings!,

In my case, MS had changed the [Advanced tab] setting for the SMTP port.
- As I said above, all remained well using Outlook at home.
- The inability to sned EMails only appeared months later when I used a hotel WiFi.

Best of luck,
Denis