Selenium Error-- Can't be able to run Firefox

I am trying to run Selenium in Eclipse. When running as TestNG it is not able to open Firefox. It closes as soon as it opens. It shows "Server not found" in the Firefox and the session is null in console. How to s开发者_JS百科olve this?

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This error occurs when either:

-The version is incompatible

OR

-The installation path given in the code is wrong

OR

-The path to firefox has spaces in between (for selenium 3.0 above)