1.7.5.2 not sending email

[Kogkalidis]

I have a client using 1.7.4.4. There is no way of sending emails to regular actions (such as on registration, on order confirmation etc).

I tried to install 1.7.5.2 on the same server, still no email.

We changed the server, installed automatic 1.7.5.2 (via a softaculous-like application) still no email.

Automatic on my own - dedicated - server (1.7.5.2) no email.

Manual 1.7.5.2 on my own server can send an email, manual on client not.

I put SMTP with correct credentials, send confirmation but no email.

Back to PHP mail() error again.

I am going insane (and the client as well).

I don't know what else to do.

Edited July 19, 2019 by tapanda.gr
Typo (see edit history)

[Rhobur]

If the test email gets sent but not the transactional email it most likely means you do not have the mailalert module installed and activated.

[Kogkalidis]

No, the test mail is not being sent, as well.
And as far as I know the mailalert module is irrelevant to the default actions (such as order confirmation).
It takes action to inform the store owner about an order or to send a message to the customer when an out-of-stock product is back in stock.

[gorkij77]

I know this one. I had to install the SendInBlue module and sign up for their servers. It's an internal mailing error related to ICU and the server side. 

Here's the github bonanza of fun ; https://github.com/PrestaShop/PrestaShop/issues/11933

Internal mail is still throwing error codes as per 1.7.6.0 albeit it should've been fixed by now...