Can´t mount encrypted external hdd after encryption was interrupted After I plug the disk it requests the password, I enter it and then it says it is not readable by my computer.

Then with Terminal I ask diskutil cs list and displays that info about the volume (see below.) Can anyone interpret this for me?  Is it possible for me to be able to recover my info? 

Logical Volume Group FFC77AC9-4B24-4D6B-9CD2-6EC58562423B
=========================================================
Name:         LaCie 4
Status:       Online
Size:         5000532242432 B (5.0 TB)
Free Space:   18919424 B (18.9 MB)
|
+-&lt; Physical Volume BF23ACC1-74C9-41D4-B9D6-6C3D6985883E
|   ----------------------------------------------------
|   Index:    0
|   Disk:     disk2s2
|   Status:   Online
|   Size:     5000532242432 B (5.0 TB)
|
+-&gt; Logical Volume Family ED69BA8E-B63F-4CDE-87EE-D36EF1BE96B9
    ----------------------------------------------------------
    Encryption Type:         AES-XTS
    Encryption Status:       Unlocked
    Conversion Status:       Pending
    High Level Queries:      Not Fully Secure
    |                        Passphrase Required
    |                        Accepts New Users
    |                        Has Visible Users
    |                        Has Volume Key
    |
    +-&gt; Logical Volume 37A4053B-08AE-4595-AA9A-67DEBEBC6C3B
        ---------------------------------------------------
        Disk:                  disk3
        Status:                Online
        Size (Total):          5000161001472 B (5.0 TB)
        Conversion Progress:   Paused
        Revertible:            Yes (no decryption required)
        LV Name:               LaCie 4
        Content Hint:          Apple_HFS
A reboot usually un-pauses conversion, so I would try that first. Consider storing the passphrase in your keychain (even if temporarily) so that it mounts when you log in and gets going on conversion after the restart. 

You are doing it perfectly - looking at diskutil cs list and checking the "Conversion Progress" and "Conversion Status" fields.

A restart might be overkill, you could try:

diskutil eject disk3
diskutil eject disk2


Once both the logical and physical volumes are detached, you could disconnect physically the drive and then wait a slow count or two and then reconnect.