WARNING 003237: Join had no matches

[Spatialelement]

I'm trying to perform a very simple join in ArcGIS Pro V2.9.0 and am getting "WARNING 003237: Join had no matches". 

I've checked the raw data for any blank values etc. I've indexed my join fields. I've converted my incoming CSV to a table stored in my projects default geodatabase. Nothing seems to be working. 

I have also manually checked my data and have confirmed that there are values that match. 

I'm trying to join a CSV to a shapefile. It has worked before (November 2021) and I am just performing the same steps, running the Add Join geoprocessing tool. I just can't work out what's going wrong.

[IlkaIllers1]

Hi,

I've had joins fail before because of extra spaces I wasn't aware of - using the trim function in Excel on the table helped with that. 

Also, check if they are stored as the same data type - I have had trouble with joins where numbers weren't stored in the same format.