iMessage Sign-In Problem

Hi,

This is problem occurring on my MacBook Air (version 10.13.4).

I am unable to sign into iMessage completely and this has been going on for the past 6 months. Whenever I try to sign in and enter my Apple ID, the following message pops up:

"Could not sign in to iMessage. An error occurred during activation. Try again."

However, the oddest thing about it is that it only does this with my Apple ID. If I type in a different Apple ID and sign in with that, then iMessage works completely fine.

Is there something wrong with my Apple ID settings or am I completely oblivious to something obvious here?

Cheers

M