[BUG] Courses update issue when IP is restricted in russia

[Mehonoshin]

Describe the bug
Whenever we run billing on Digital Ocean VPS, it tries to update exchange rates via russia_central_bank gem.
Unfortunately for some reason it does not work, though it worked on some other VPS.
Probably that may happen because of goverment restrictions. We need to investigate and fix that.

To Reproduce
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2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior
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Server (please complete the following information):

• OS: [e.g. iOS]
• Browser [e.g. chrome, safari]
• Version [e.g. 22]

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
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