How to solve? Notifications: failed send request (HTTP session creation failed [15105])

 

I try to send notifications to my phone, but in the journal I see "Notifications: failed send request (HTTP session creation failed [15105])"

Is some program missing or a firewall rule? It fails even if I turn the firewall off, so I think it is not a firewall issue, but then what? I'm running MT4 on a Windows server 2008 R2.

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