Fixer IO Sharp Api response "Could not get CurrencyResult for one or more reasons"

Question

I am trying to get the latest exchange rates from Fixer IO Sharp but have been getting this error for the last week or so:

"Could not get CurrencyResult for one or more reasons"

The code was running fine before that.

Here is how, I am making API calls to Fixer IO Sharp:

var client = new FixerIOClient()
{
    BaseCurrency = baseCurrency,
    Symbols = baseCurrencies
};

var result = exchangeRateDateTime == null ? client.GetLatest() : client.GetRatesForDate((DateTime)exchangeRateDateTime);
var rates = result.Rates;

Calls to client.GetLatest() and client.GetRatesForDate() method generates this error.

Any idea what could be the issue?