Cannot connect to SuiteCRM with Thunderbird Plugin

[BluesGhost]

My apologies if I’m posting this in the wrong category, but I didn’t see dedicated one for Thunderbird plugin/add-on

I’ve installed SuiteCRM under my website via admin-panel of my hosting company.
I then downloaded the Thunderbird plugin following the link provided at SuiteCRM Store | SuiteCRM Module, Themes, and Integrations

The installed SuiteCRM is:

• Version 7.1.5
• Sugar Version 6.5.20 (Build 1001)

Unfortunately, I keep getting an error from the Thunderbird plugin stating that it is unable to connect and to verify the URL.
URL and login credentials are perfectly fine (verified numerous times).

However, the TB error console is logging the following error:
OpacusSTP bailing on client return status: 403)

I’ve opened a ticked with the hoster and their final findings are as followed:

It seems that you are getting denied by your application itself:

Code:
[Mon Feb 16 07:20:58 2015] [error] [client 50.172.122.65] client denied by server configuration: /home/xxxxxxx/public_html/xxxxxxx.com/SuiteCRM/index.php
[Mon Feb 16 07:23:55 2015] [error] [client 50.172.122.65] client denied by server configuration: /home/xxxxxxx/public_html/xxxxxxx.com/SuiteCRM/index.php
[Mon Feb 16 07:24:35 2015] [error] [client 50.172.122.65] client denied by server configuration: /home/xxxxxxx/public_html/xxxxxxx.com/SuiteCRM/index.php

Can someone please assist on how to resolve this issue?
Thanks in advance for your help!

[Will]

check your permissions are correct.

what is your environment/server setup?

[jkoppert]

Hi,
I realise this is an old post, but I seem to have this problem right now.
Any advice on what need to be changed to the permissions and how?
(sorry no expierience with this…)

Thanks

JP