Investment advise UK

I am an international student in the UK and have some spare cash that I’d like to invest with minimal risk. I applied for a Sharia-compliant savings account through Raisin, but my application was rejected without any explanation.

I’m looking for alternative low-risk, Sharia-compliant investment options. Ideally, something accessible without requiring permanent residency.

Has anyone faced a similar issue with Raisin? And what other options would you recommend?