Error loading conditions into a trial

I am creating a memory experiment and I tried to upload my excel file with the names of the stimuli in the encoding trials properties “conditions” space. However when I press upload, I get the following error

Traceback (most recent call last):
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.6/psychopy/app/builder/dialogs/init.py”, line 1605, in onBrowseTrialsFile
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.6/psychopy/data/utils.py”, line 338, in importConditions
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.6/psychopy/data/utils.py”, line 256, in _attemptImport
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.6/psychopy/data/utils.py”, line 301, in pandasToDictList
File “/Applications/PsychoPy.app/Contents/Resources/lib/python3.6/psychopy/data/utils.py”, line 276, in _assertValidVarNames
psychopy.exceptions.ConditionsImportError: Conditions file /Users/gracegervino/Documents/encod_for_psychopy.xlsx: Parameters (column headers) cannot contain punctuation or spaces

“Face Stim “

Hi I have faced the same problem. Are you able to solve it?

Columns in your spreadsheet must not contain spaces since they are used by PsychoPy as variable names.