Weird Security alert in shop

Not quite sure if this is the right board but here's my problem I recently came upon a unnerving alert whenever I entered the shop, it told me I did not have a secure connection, and that the sites didn't match or something like that. the reason i find it unnerving is that i occasionally purchase RP from the store and I'm wondering if it is still secure to purchase it is still safe. and what I can do to fix it. any assistance in this matter would be greatly appreciated.