Airtag - no beep while replacing my battery

I replaced my batteries of my Airtags and they are not connecting to my devices anymore. Following all the steps outlined I noticed that 3 out of 4 of my airtags do not give a sound when I push the battery down. One airtag is still working perfectly, before replacing teh batteries the other 3 also worked OK. What can be wrong and how do I solve it?