Error: 404: on Salesforce HTTP request

URL: https://tilth.my.salesforce.com/services/data/v50.0/sobjects/Web_Ticket__c/tmp_sf_6356fc9cc1dda2.76072370

Message: Provided external ID field does not exist or is not accessible: tmp_sf_6356fc9cc1dda2.76072370

Code: 404