Commented Unassigned: Server Failed error [9679]

The smtp4dev worked fine just fine, next time when I re-downloaded and tried to use it , it gave me error:
Only one usage of each socket address is normally permitted.
Even after port from 25 to 0, the error will go but no emails are showing up in the tool. PLease help.
Snapshot attached.
Comments: ** Comment from web user: Fanna **

The smtp4dev worked fine just fine, next time when I re-downloaded and tried to use it , it gave me error:
Only one usage of each socket address is normally permitted.
Even after port from 25 to 0, the error will go but no emails are showing up in the tool. PLease help.
Snapshot attached.