The issue is likely caused by a mismatch between the data type of the column in Power BI and the actual data in the Excel worksheet. The colon (":") in the contract number is most likely causing Power BI to interpret the column as a different data type, leading to the binary error.
A solution to this issue would be to remove the colon from the contract number in the Excel worksheet or to modify the data type of the column in Power BI to match the actual data. This can be done by going to the Power BI Desktop, clicking on the column header, and selecting a new data type from the dropdown menu.
If you're unable to modify the data in the Excel worksheet, you could also try creating a calculated column in Power BI that removes the colon from the contract number before it's imported into the report. This can be done using the DAX formula, such as =SUBSTITUTE(<column name>, ":", "").
It's always important to review the data type of columns in your reports to ensure they match the actual data and prevent errors during the import process.