Check the data types in the data model and data source and ensure that the data types are compatible

Misha It is not clear what type of data connection you are using. But looking at your issue, it more likely to be an issue with data conversion issue. These error snormally occurs with date or numberic values which are many times automatically converted by powerbi engine during data load in power query window. And after a while if there is any value which is not compatiable with the data type of the converted field then error may occur. I would suggest you to enable column quality in the power query window, to check the quality of the data in each column and then check which column has issue.

 let me know if above suggestion can help you to resolve your issue.