Here are links to different Knowledgebase Articles:

Error: "You are not currently set up as a user of the selected Estimating server" (Windows Username changed) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server" (Check with your Administrator) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server" (Security.Fix required) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server." (User Profile Issue) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server" (No Features are added to the Role selected) (Estimating SQL) 

Error: "You are not currently set up as a user of the selected Estimating server" (Local user account needs to be added at server) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server." (Windows email login or Microsoft Account) (SQL) 

Error: "You are not currently set up as a user of the selected Estimating server" (Computer name changed) (SQL)