Datenum problem and reading from excel sheet

How can I fix it? I'm reading from an excel file

[Robert U]

Same question as here:

https://de.mathworks.com/matlabcentral/answers/348247-datenum-error-how-to-fix

Please, check my comment on that.

Answer 1

[Jan]

The error message is clear: raw_bouts_data(2:end,5) is not a cell string. Check this:

find(~cellfun('isclass', raw_bouts_data(2:end,5), 'char'))

What do you find? What are the types of the cell elements?