Problems connecting from car to landlines

Have just taken delivery of 2021 Tucson Hybrid, absolutely wonderful car, but have problems phoning from the car. I can call mobile numbers no problem but although I can get through to a landline the recipient can't hear me. Thought initially it was my phone, but it works fine in my wife's Ford Focus. The phone is paired and all my contacts have successfully downloaded. Because I have to call my employer's landline number regularly whilst driving, its become a pain having to pull over to ring them. Does anyone else have any suggestions? Thank you.