Hi @maxwilliams.boko,

Would you be so kind as to (i) let us know which version of Python you are using, (ii) which IDE you are running your code in, (iii) what OS you are running it on (Windows? MacOS? ...) and also (iv) share your code with us - what code did you run to come up with this error?

As I can see from the error message, you are using Anaconda and this error is coming since Eikon API is making use of nest_asyncio.py file. asyncio only generates an event loop for the main thread but in your case asyncio.get_event_loop() is running in some other thread instead of main thread.
So a quick fix for this is to locate apply function in nest_asyncio.py file which is available at anaconda site packages folder:

def apply(loop=None):
    """Patch asyncio to make its event loop reentrant."""    
    loop = asyncio.get_event_loop()
    if not isinstance(loop, asyncio.BaseEventLoop):
        raise ValueError('Can\'t patch loop of type %s' % type(loop))
    if getattr(loop, '_nest_patched', None):
        # already patched        return    _patch_asyncio()
    _patch_loop(loop)
    _patch_task()
    _patch_tornado()

and replace

loop = asyncio.get_event_loop()

with

loop = asyncio.new_event_loop()
asyncio.set_event_loop(loop)

This will start a second event loop to run and will fix this error.

I had the same problem and didn't manage to solve it with the proposed solution. I therefore deleted the lines of frontendcomm.py :

 else:  
     #This is needed for ipykernel 6+
     asyncio.run(handler(out_stream, ident, msg))

and it works well !