I am not to sure if this question belongs here but I will surely find out soon enough.

I have two web hosts (Not sure why it has been setup this way but it has). I do not want to use the original web host to handle the emails as the Data that we get from them is 500 mb which is already full with hosting the website. The second web host has an unlimited data plan and was created so we could use this host for the email accounts.

Now the problem is I have reset the Advance DNS Zone records on both accounts and I am not sure what they were before. (Silly me should have taken a backup of how it was setup before hand I know) Emails were working before and going to the second hosts server now they are going to the first host but it has no email addresses setup for use so all emails are bouncing saying that the address does not exist.

Host 1 IP: 192.185.96.110
Host 2 IP: 27.54.88.66

So far I have changed the Advanced DNS Zone record on Host 1 with the following:
A Record: mail.australisinstitute.qld.edu.au -> 27.54.88.66

I have not made any changes on Host 2 and both hosts have the default MX Records.

If I need to provide any more information I can but I just hope someone can decipher what I have said haha.

Cheers in advance!