error, string or binary data would be truncated when trying to insert

From @gmmastros's answer

Whenever you see the message....

string or binary data would be truncated

Think to yourself... The field is NOT big enough to hold my data.

Check the table structure for the customers table. I think you'll find that the length of one or more fields is NOT big enough to hold the data you are trying to insert. For example, if the Phone field is a varchar(8) field, and you try to put 11 characters in to it, you will get this error.

I had this issue although data length was shorter than the field length. It turned out that the problem was having another log table (for audit trail), filled by a trigger on the main table, where the column size also had to be changed.