Long distance bf too tired to talk on the phone

My boyfriend and I use to talk on the phone Every other day but lately he’s been telling me he’s too tired and he would talk to me at some point the next day but it doesn’t happen. It’s not like I can get mad at him for sleeping but he’s also been texting me less and idk... i don’t want to loose this relationship but I feel like he doesn’t want it sometimes and I put in all the effort.