Access to MyCloud by remote users - which URL?

I have an EX4100 which I have been successfully using to backup my PCs (using Acronis) and hold my photographs which I can view using my “WDPhotos” (iOS) and Mycloud via a browser. Now I would like to share the photographs (and possibly other items) with family who live across the globe. I may also wish them to add material to a family “archive”.
I have set up user accounts with e-mail addresses and passwords, and provided read access to the appropriate shares. HOWEVER, when I try and log into MyCloud with the email address and password - it fails with an invalid password. I suspect that I am using the wrong URL (mycloud.com which maps to files.mycloud.com/login.php) and so it is treating my relative as if he is a device owner.
What URL should he use?

First, you may have better luck in the dedicated EX subforum where people more knowledgeable about that unit may be able to assist, and where you can search (magnifying glass icon upper right) for past discussions similar to your issue. This subforum (My Cloud) is generally for the single bay/single drive My Cloud units which are different than the EX series.

https://community.wd.com/c/network-attached-storage/my-cloud-expert-series

For the single bay My Cloud units one generally uses http://files.mycloud.com/. One needs to ensure they have properly setup the user through the My Cloud Dashboard > Cloud Access section as well as enabling Remote Access through the My Cloud Dashboard > Settings section. The EX Series may have a different procedure for enabling remote access. Make sure to consult the My Cloud Support section for the EX 4100.

https://support.wdc.com/product.aspx?ID=2702&lang=en

Hi - many thanks for your response - I will certainly move my request to the EX forum. I will also double chec the things you suggest.
Somewhere I read that my brother’s account needs to be verified which is done by him clicking on a link in an email that MyCloud sends him - but he didn’t spot one and O I will also ask how to resend it.

Many thanks again

The way it generally works is after creating a User through the Dashboard and granting cloud access to that User, the user receives an email. The user then goes to the MyCloud.com website and creates an account if they haven’t created one previously. That account is separate from the Dashboard created User account. Once the user creates the MyCloud.com account and logs in using that account information they should be able to access the My Cloud remotely.

The My Cloud Learning Center should have additional information on remote access as should the user manual for your My Cloud model.

http://learn.mycloud.com/