Reject Code R0000-198 is an error code generated by the Internal Revenue Service (IRS) when there is an issue with your tax return. Specifically, this code indicates that the IRS was unable to process your return because the taxpayer identification number (TIN) on your return does not match the TIN in the IRS's records. This can happen for a number of reasons, such as a typo or a name change that has not been updated with the IRS.

To fix this error, you will need to take the following steps:

1. Double-check the TIN on your tax return to ensure that it matches the TIN on any other documents you have received from the IRS (such as a previous year's tax return or a 1099 form).

2. If you believe that the TIN on your return is correct, you should contact the IRS to inform them of the error. You can do this by calling the toll-free number listed on your rejection notice or by visiting a local IRS office.

3. If the TIN on your return is incorrect, you will need to file an amended return with the correct TIN.

In either case, it is important to take action as soon as possible to avoid further delays in processing your return and potential penalties or interest charges.