We need more information - see this post and come back with more detail on the problem, include which OFX plugins,how you have 'installed' them and how you are trying to use them.
I've installed MEP premium 2017and all is working except I cannot get Filmconvert OFX plugin to be recoginised.
The plugin installed to c:\program files\common files\ofx\plugins and I've tried installing them in the media pool >advanced >add search path etc. Nothing.
Running win 7 pro 15 4670, geforcegtx970 16 gb RAM
Any suggestions or even other OFX that I might try that has worked for others?