Per the IRS Instructions for Schedule SE (Form 1040) Self-Employment Tax, page SE-2:
U.S. Citizens or Resident Aliens Living Outside the United States
If you are a self-employed U.S. citizen or resident alien living outside the United States, in most cases you must pay SE tax. You can't reduce your foreign earnings from self-employment by your foreign earned income exclusion.
Exception. The United States has social security agreements with many countries to eliminate dual taxes under two social security systems. Under these agreements, you must generally pay social security and Medicare taxes to only the country in which you live.
The United States now has social security agreements with the following countries: Australia, Austria, Belgium, Brazil, Canada, Chile, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Luxembourg, the Netherlands, Norway, Poland, Portugal, Slovak Republic, Slovenia, South Korea, Spain, Sweden, Switzerland, the United Kingdom, and Uruguay.
If you have questions about international social security agreements, or to see if any additional agreements have been entered into, you can visit the Social Security Administration's (SSA's) International Programs website at SSA.gov/international. The website also provides contact information for questions about benefits and the agreements.
If your self-employment income is exempt from SE tax, you should get a statement from the appropriate agency of the foreign country verifying that your self-employment income is subject to social security coverage in that country. If the foreign country won't issue the statement, contact the SSA Office of International Programs. Don’t complete Schedule SE. Instead, attach a copy of the statement to Form 1040 or Form 1040-SR and enter "Exempt, see attached statement" on Schedule 2 (Form 1040 or 1040-SR), line 4.
To remove Schedule SE from your TaxAct® return if necessary:
Note. Due to the need to enter text on Line 4, and to include the statement, the return would need to be paper filed. Click Filing and select Mail My Return to complete that process.
Please refer to IRS Publication 54 Tax Guide for U.S. Citizens and Resident Aliens Abroad for additional information.