RoundCube + Gmail --> Connection to the storage server failed

[Achi]

Hi all ,
I tried to install roundcube on ubuntu 16.04 and the process was done .
Db and user are okay . In the finish step , when the installer ask me to check the connection or to try to send email , i get a NO OK message . I enabled the IMAP option on gmail and i used 993 and 587 .
When i try to access to my email i cant and the message : connection to the storage server failed .
Can you help me ?

[SKaero]

Check if a fire wall on the server is blocking access.

[Achi]

Thank you for your replay . I'm new with this stuff, can you explain me a little bit please.
How can i check it ?
Thanks.

[Achi]

The firewall is inactive . Any propositions ? Thanks

[Achi]

I tried with yahoo account and i reinstalled roundcube but same issues : connect to the storage server failed !

[SKaero]

My guess is that something is blocking out bound connections from the server to the mail servers. If there isn't anything on the server maybe something is blocking it in the network?