HTTP Error: 403 "Forbidden"

Hello support team.

Since yesterday i am member at wpmu dev and want to install the wpmu dev dahsbord.
The following error is displayed after try to sign in:

Your server had a problem connecting to WPMU DEV: "HTTP Error: 403 "Forbidden"". Please try again.

If this problem continues, please contact your host with this error message and ask:

"Is php on my server properly configured to be able to contact https://premium.wpmudev.org/api/dashboard/v1/ with a POST HTTP request via fsockopen or CURL?"

I already contacted my hosting provider (a2hosting.com).
There was a support staff called Wolf. He told me he is also long time WMPU DEV Member and had the same problem in the past, but send me the following advice:

Hi and thank you for contacting A2 Hosting. My name is Wolf and I thrilled to help you. I am so sorry to hear you are having this problem. I am happy to help you resolve it.

I have been a longtime subscriber to WPMUDev myself, so I am quite familiar with their plugins. Fortunately, this also means I have experienced this error myself. What you want to do here is contact WPMUDev support and give them your servers IP address and ask them to whitelist it. For some reason, their API sometimes blocks IP addresses, so they need to be whitelisted.

The IP is 75.98.175.115

Hope that you can support me asap.
Thanks for your time.
I look forward to hear from you.