email service is erratic .

two days ago I could send and receive and send emails over night i could no longer send them and now I can no longer receive them.

I have the following:

1 email address that i use to log into my online vm account. I'll call it account 1

I have 3 email accounts that i use for personal emails. which I'll call  account 2,3 and 4

I use a mac computer and an iphone 11, and use Mail ( the mac mail service for emails

I can't use the vm app as its not compatible with my devices...

I don't understand why I this suddenly stopped working, nothing has been changed by me.

 This all started last year when the same situation occurred and I was told I needed to set a a special password via a link on the vm page, it was 3 word password. that took over 3 hours spread over 2 days.

i managed to get 2 addresses working on my phone  ( mail 2 and 3)and two on my mac ( mail 2 and 4) so covered them , but was not very convent . Ive so far spent a very long  afternoon trying to figure it out.

please can some one explain to me in simple terms.. like i'm a 5yrs old would help, because I am fed up of CS raising their voice because they think i'm deaf ! sentences like your 'main email address' I assume means the one i log into my vm account with... apparently not, after an hour and a half i get one working and the CS agent says now just do the same for the others !

imaging to lie in a darkened room for a while.

thanks if anyone can help