mail clients cannot connect

[Ricksta V]

Hi 

I am writing to get some help if I may please.

I have installed and configured chasquid and dovecot exactly to the instructions. I am using Ubuntu  20 something.

Yes new to linux and doing my head in fast.

I have added users to the respective domains, certbot working etc etc.

Any mail client I am attempting to use cannot connect.

I am chiisung pop 3 access from the lists

entering username (email address)

password

now I have tried every conceivable point from here

I have chosen startTLS Plain port 995 - verified open and routed

selected start TLS on smtp port 587 - verifpied open and routed

Please, may you offer a solution?

The client I have chosen is on google play.

Aqua Mail.

If you want to see logs etc, please be very specific on what I need to put int o the teminal.

sudo xyz -abc

Best Regards

Rick