Hi,

The error 99173 is a general error number: the description will give details.
In a T1 - transmitter number is your efile number. Enter that in Efile> set efile password. Make sure to use the latest efile password and enter with cap locks on.
In a T1-Represenative ID means a RepID of less than 7 digits is entered in Option >environment, Preparer tab. If you have a seven digit RepID enter it there. CRA guidance is in 2022 the RepID is optional for the T183

See CRA efile news for more information
https://www.canada.ca/en/revenue-agency/services/e-services/e-services-businesses/efile-electronic-f...