Hi there! This is a common error, but that also means that there are many potential steps to try. First, please make sure that your graphics drivers are updated. Then please make sure that you are opening Uplay and For Honor as administrator. If neither of those steps help, you can try reinstalling For Honor. If that doesn't help, please reach out to our technical support team.
I can tell you that all of those "steps" not working 100% for me I even re installed this game, almost 50 gigs at speed of 600kbps like a moron and nothing! It's 2 months now since patch 1.9 I believe, after pouring 70 Euros and hundreds of hours into this game I am now unable to enjoy it like rest of you.
This is a very common and extremely annoying error. It happens becouse there is a conflict between your 64 and 32 bits windows .dll files (located on your "System32" and "SysWOW64" folders) . I've got this error as well, have 100h+ played and not even 1 issue before this (I've been using windows 8.1 pro 64bit long before I got the game). Well, I contacted the ****ty ubisoft support and they kept saying that the reason for the problem was a lack of some forwarded ports on my modem... the only "solution" I've got left is to change my windows to something different since I've tried more then 8 different .dll file packs and none worked.