Mac - Not connecting on File Sharing

I have a Macbook Pro which I am trying to connect to my iMac remotely.  Share Screen works perfectly but when I try to connect for file access only it says Connection Failed.

I have Backup to my Mac enable on the Airport Extreme.

Under Sharing, I have file sharing enabled and I am listed with Read/Write, as is Administrators (which I am one).

I have tried connecting with both Registered User and with the User credentials.

The firewall is disabled on the iMac.

I have the latest o/s on both Macs.  All software is to date.

Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

Did you read this Apple KB:  ?

In particular,

In Airport utility, select the AirPort base station that you want to use with Back to My Mac, and click Edit.

Enter the base station password. This password is different from your iCloud password.

Select the Base Station tab.

In the Back to my Mac section, click the + button and enter the Apple ID and password you use with Back to My Mac. You should see a green status indicator showing that Back to My Mac is turned on.

Click Update to save your changes.
PowerhousecomputingAuthor Commented:
This has already been checked and the light is green.
On the target computer, go to:

Apple Menu > System Preferences > Sharing

Click on the Options button and make sure you have both AFP and SMB file sharing turned on.
Protecting & Securing Your Critical Data

Considering 93 percent of companies file for bankruptcy within 12 months of a disaster that blocked access to their data for 10 days or more, planning for the worst is just smart business. Learn how Acronis Backup integrates security at every stage

PowerhousecomputingAuthor Commented:
Why? Surely this is only for Windows?
PowerhousecomputingAuthor Commented:
Actually just checked and they are enabled anyway.
You need at least AFP checked. It doesn't hurt to check SMB as well. Apple is gradually moving away from AFP to SMB.
Can you post a screen shot of your main sharing prefs window?
How are you connection to the file share?  What commands?  What share name?
PowerhousecomputingAuthor Commented:
Connection through finder - select the device and it should connect.
Command Shift 4 to select an area for a screen shot.  You can also press the space bar right afterwards to toggle capturing a selected window.  Please show your prefs window as Strung has asked.  Since you're selecting the share through the finder, it suggests that you can see the share.  The only thing left is a permissions mismatch.
... or a wrong username or password ... which is why I asked for a screen shot.
PowerhousecomputingAuthor Commented:
If I have re-entered all passwords could it still be a mismatch - should I check keychain for example ?
Please post a screen shot of your sharing prefs pane.
PowerhousecomputingAuthor Commented:
Where do i find the specific passwords in keychain ?
You need to post a screenshot of your sharing prefs pane so we can figure out what username and password to use.
PowerhousecomputingAuthor Commented:

I should add that when I am on the same network it works fine - it's only when I am outside.

This to me would point to an Airport Extreme issue ?
PowerhousecomputingAuthor Commented:
I have sorted it - I remove my credentials in Backup To My Mac on the Airport Extreme and restarted then put them in again and restarted - now working.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today
Mac OS X

From novice to tech pro — start learning today.