Invalid Credentials for Gateway connection to source file

I have a dataset and Power Bi report changed from a local account on a PC which was running fine: Gateway setup was ok and I was able to refresh the dataset periodically. However, I wanted to change the setup so I can use an account for the local PC that is using my Office account. I have changed this all and I can make a connection to to the dataset, however, I can't seem to get the Gateway to connect to the dataset due to appearantly incorrect credentials.

- The Gateway is online.

- The dataset seems to be accessible - in the settings part of the dataset I can see the Gateway being executed on the local PC.

- The path to the dataset is ok.

Only part that I cannot seem to fix is the invalid credentials. I must be overlooking something, but not sure where to look. 

• error":{"code":"DM_GWPipeline_Gateway_InvalidConnectionCredentials","pbi.error":{"code":"DM_GWPipeline_Gateway_InvalidConnectionCredentials","parameters":{},"details":[{"code":"DM_ErrorDetailNameCode_UnderlyingErrorCode","detail":{"type":1,"value":"-2147467259"}},{"code":"DM_ErrorDetailNameCode_UnderlyingErrorMessage","detail":{"type":1,"value":"De referenties die zijn opgegeven voor de bron File, zijn ongeldig. (Bron op c:\\users\\xxxxxx\\xxxxx\\omzetstatistieken - documenten\\geautomatiseerde taken\\omzetrapportage\\omzetgegevens_totaal.csv.)"}},{"code":"DM_ErrorDetailNameCode_UnderlyingHResult","detail":{"type":1,"value":"-2147467259"}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourceKind","detail":{"type":1,"value":"File"}},{"code":"Microsoft.Data.Mashup.CredentialError.DataSourcePath","detail":{"type":1,"value":"C:\\Users\\xxxx\\xxxx\\Omzetstatistieken - Documenten\\Geautomatiseerde taken\\Omzetrapportage\\Omzetgegevens_Totaal.csv"}},{"code":"Microsoft.Data.Mashup.CredentialError.Reason","detail":{"type":1,"value":"AccessUnauthorized"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.DataSources","detail":{"type":1,"value":"[{\"kind\":\"File\",\"path\":\"C:\\\\Users\\\\xxxx\\\\xxxx\\\\Omzetstatistieken - Documenten\\\\Geautomatiseerde taken\\\\Omzetrapportage\\\\Omzetgegevens_Totaal.csv\"}]"}},{"code":"Microsoft.Data.Mashup.MashupSecurityException.Reason","detail":{"type":1,"value":"AccessUnauthorized"}}],"exceptionCulprit":1}}} Table: Omzetgegevens_Totaal.
• URI clusterWABI-WEST-EUROPE-B-PRIMARY-redirect.analysis.windows.net
• Activiteits-id21921e6b-6bb6-461a-822e-58171d3d4994
• Aanvraag-idead08552-5fb1-7c44-ddc2-aeb5dd44327d
• Tijd2024-09-01 06:26:00Z

 I'm out of ideas where I should amend the credentials.