Try changing it to the 'Select server automatically' option in the Electrum Network settings. Restart Electrum, and try changing the settings again using your Electrum Server.
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That's weird we are using the same version of Electrum, but yours shows more options than mine, even the new Bitstamp and Bitfinex.
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Ow I get it like nc50lc said if you uncheck the download historical rates, you can see other source but when you enable it, it shows limited source.
The fiat currency chosen also affects the source list. The following example compares USD with IDR (Indonesian currency):