Cannot hear incoming caller when using headphones - Apple 12

When using iPhone 12 with corded earphones - cannot hear incoming caller. Caller can hear me, I cannot hear caller through earphones, but can hear from phone. Earphones work fine with all other functions XM, online, etc. Have tested corded iPhone earbuds, Samsung corded earbuds, and Jabra over the ear headphones with same results. I need to use over the ear headphones because of some ear issues (not hearing issues).

Thanks for any help!