Hello CARLA84
Welcome to the Community Forum.
Invalid characters are "[ ] ! # $ % * ; = @ <>\ _ { } ^~`" so the & symbol shouldn't be causing this. When you removed the space in between the phone numbers, did you also check that there was no space entered in at the end of the phone number or addresses, these can sometimes cause the error to pop up and are harder to notice due to being at the end of the entered information.
When you check that can you also please let me know if the error message identifies a particular line the error is happening with.
Please let me know how you go.