Hello @lorenzolodi66,
My name is Henry and I am happy to assist with your inquiry, and appreciate you contacting LastPass Support!
I am sorry about the issues you are having with your password. The user of emojis is not supported as a password stored in LastPass. I would suggest changing the password without using emojis.
Please let me know if this worked or if further assistance is required.
Thank you,
Henry | Customer Care