421 Service not available, closing transmission channel (in reply to EHLO command)

[gabwil]

My father tried to send me an email to my TPG email address yesterday, and the email still hasn't come through.  He received the following bounceback. What does this mean?

"[tpg email address] delayed: host asav.tpg.com.au (27.32.32.10) said: 421  Service not available, closing transmission channel (in reply to EHLO  command)"

I also just tried to send an email to myself from a different email address, and the email hasn't been received.

[Ahra_G]

Hi @gabwil, 

I would recommend to send this error directly to our PostMaster at postmaster@tpg.com.au

Please ensure to include your username and the problematic email address.

Thanks! 

Ahra_G