Not sure if I followed your step 2 correctly “Follow the installation instructions for Admin/repair/ email accounts” - can you please give more details on what should be done here.
I have also established that it is somehow a database issue as I have fixed it to working again.
When checking the MAMP database I saw that there were other email outbound and inbound settings that I had not put there and it appears that SuiteCRM was using them. These other settings must have been somehow entered after I installed it earlier today, perhaps some code or whatever that is not doing what it is supposed to. I deleted them and reentered the same as I did before and now it sends emails again.
The question I have is why is this happening? Could anyone involved with development please forward this on, if it is helpful.