Yes, the limit is 50,000 characters. I'm assuming what you're pasting is including a lot of mark-up, which isn't counted in word. Try pasting it as plain text. If you're on a Windows desktop, you can do that by right-clicking and clicking "Paste as plain text" or by using "CTRL+SHIFT+V". On Android, long press, then click "Paste as plain text". I'm sure there are similar methods on Apple, but I wouldn't be able to tell you exactly how to do it.
