Power Query DataSource.Error: ODBC: ERROR [08S01] Communication link failure:

I made an Excel/Power Query using ODBC to read my database (in 4D Database). Everything worked just right.

Then I  saved and closed Excel. Next day when I opened the workbook, I found that it didn't work anymore.

The error I received was something about it couldn't convert the Unicode character \uDC12 of the index 5.

 But I suspect that the real problem is similar to another I had when I made my querys using Excel - Data / From Microsoft Query, because the behavior was similar: I did my query, it worked perfectly, but when I tried to use it next time (after saving), It gave me this errors:

If I'm right, the problem is that somehow Excel forgets the instructions and/or credentials to connect with the database.

Can somebody help me?