I filed for a federal automatic extension by using an electronic payment method via the irs site, got approved. But then went ahead and filed the federal tax form today and it was accepted. But I forgot I was holding off on filing my taxes (hence why I got the extension) to make a contribution to my solo 401k, which I know I technically would have had until October 15 to contribute. Even though I filed for an extension until October 15, but I already e-filed just now, can I still contribute to my solo 401k by October 15, or at least in the next few weeks without amending my return?
(My other question identical to this was closed without answers after only a few hours so posting again because that seems like it was a mistake)
