Imessage won't activate on Ipad

I have a wifi IPad I purchased a few months ago. I use it for work because with my bluetooth keyboard, it's easier to answer multiple texts from clients. Recently, Imessage stopped working on it. When I try to sign back in, it says "imessage activation... an error occurred during activation. try again." I've already factory reset the ipad, updated to the newest ios, and checked that time/date is on "automatic". I still can't verify or activate my imessage. Please help!