Sometimes you’ll find you can’t get travel insurance while you are already outside of your home country.
For example if you are from the UK and already outside of the UK you’ll find most if not all won’t give you cover as you are already outside of the country, you have to have done it before you left.
I took a one year health insurance policy ( in-care ) out for Thailand which gives me 45 days per year outside of Thailand if visiting other countries, and I also get coverage in my home country.