Increase email sending speed


I have got mailwizz server with 3 smtp servers.
Settings are: 100 emails per min, 100 subscribers at once, pause 10 sec, 200 email before pause, change server every 1 server (one by one). Each smtp server have limit about 2000 email per hour.
I have a problem with email sending speed. I can send only 100 email per 10 min using this 3 servers. I want to speed it up.

So I created a test compaign to send email to my list (600 test subscribers on my remote mailserver).

Regarding your doc:

I've checked where is the problem.
As I could see the problem is:
1) mailwizz trying to connect to each smtp server one by one
(prepairing email->connecting to server 1->sending
prepairing email->connectiong to server 2->sending) etc....
2) connection to every smtp server take about 5 seconds each time.

Is it possible to parallel send email via this 3 smtp servers (or more smtp servers) from 1 campaign?
If the connection takes 5 seconds then you should really look into why it takes so much.
If the latency between your server and the smtp servers is that much then you should do something about it.
DNS server should also be taken into consideration, maybe use google dns servers

If latency can't be lowered, then maybe look into

Thanks! As I can see this problem appears only when I'm using remote smtp, with local smtp account on server there is no problem.
Anyway this is not mailwizz problem, maybe with exim4... Will check it.

The last question about command:
/usr/bin/php -q /var/www/html/apps/console/console.php send-campaigns --verbose=1
Can I get more detailed output with that? maybe there is --verbose=5 key or somethink else?