Outlook for Windows does not render email with a browser engine, but with Word's, which ignores much of modern CSS. That is why signatures formatted with current techniques get misaligned just in the client where they are most used.
The signatures from this tool are formatted with HTML tables precisely to avoid this. If it still gets misaligned, it is almost always due to one of these three reasons:
- You pasted the signature after going through Word or a text editor, which adds its own formatting.
- You pasted as plain text and lost the table structure.
- You edited the signature manually within the Outlook editor, which rewrites the HTML when saving.
The solution in all three cases is the same: delete the signature, copy it again from this page, and paste it directly into the signature editor without editing it.