Email plus other stuff

Question

My email is periodically coming up with an err message can't send message using server
then gives me the option of clicking on the correct smtp name boom it then goes through
if I then click on connection doctor all the settings are checked and come back with green lights.
Whats strange these email settings work fine on my iPad air plus iPhone - does anyone have any suggestion?
The other thing I'm trying to get my head around I've made a wired connection to my mac and orange hub if I turn on the wifi does this stop the wired connection and revert to a wifi connection?
I have a wifi printer and its a real pain in the *** to have to keep turning on the wifi to use printer. I was hoping that once I've made a wired connection I could leave my wifi on so I could use my wifi printer.
Is there a way to tell me whether I've got a wired connection to my hub or whether its going through wifi?

Answer 1

Right, sir. Went to the genius Bar, ordered a vodka and coke, then got down to business. As predicted, my iMac connected immediately to their 5GHZ "Demo" network. But we managed to suss out what was going on at home...
Here's what my issues were down to:
The UK restricts the use of 5GHZ frequencies as we have our BBC and other organisations who rule over the distribution of radio frequencies in order to make money etc etc. So the iMacs sold over here aren't enabled to pick up certain frequencies.
Also, my Airport Extreme BS was bought from my recent visit to the US, so that also has "different" frequencies that it broadcasts. So, between them, they weren't able to shake hands. My slightly older MBP and iMac Core2Duo, are not afflicted with frequency restrictions, so they were able to pick up the 5GHZ frequency without being arrested by the Radio Police.
The Genius suggested a way round the problem, and it worked:
Connect a modern Airport Express n to the AEBS with an ethernet cable, and set it up as a Bridge, and to Create a network - 5GHZ ONLY. Name the new network, input WPA2 or whatever is your preference, and press "update" when all is done. Now, the new 27 inch gets, 300 megawotsits, as does the MBP and the other iMac gets 270 megawotsits (not sure why it gets less). All the other older Macs get either 130 or 54 depending on age, but the Macs upstairs the previously struggled to get a wireless signal at all, now get full bars - probably because I have closed down the WDS setup I was forced to use because of the decayed wireless signal up there.
So, all is well. Two networks, one fast, one not quite so, but working very well nevertheless.
I hope that helps anyone else trying to achieve the same thing.
Many thanks to myhighway again for all your time and input. Nice one.
Best wishes from Cheshire, UK, and have a Happy New Year!
Cheers
Chris