Cannot decrypt message: no shared key yet

I run npool on all my instances (5 VPS’s) for well over a month.
Since yesterday, I’m constantly seeing messages like this:

2023/03/26 15:31:13.114250 [WARN ] GID 324535, Decrypt message from <45.79.152.165:36028> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.114458 [WARN ] GID 324178, Decrypt message from <44.234.23.86:38652> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.114717 [WARN ] GID 325129, Decrypt message from <173.255.225.244:56612> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.115575 [WARN ] GID 325909, Decrypt message from <137.184.114.95:47610> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.115733 [WARN ] GID 325909, Decrypt message from <137.184.114.95:47610> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.115908 [WARN ] GID 325918, Decrypt message from <18.246.46.106:54538> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.116062 [WARN ] GID 325918, Decrypt message from <18.246.46.106:54538> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.121286 [WARN ] GID 324934, Decrypt message from <146.190.161.228:51796> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.164698 [WARN ] GID 325136, Decrypt message from <173.255.225.244:56612> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.206752 [WARN ] GID 324534, Decrypt message from <45.79.152.165:36028> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.222635 [WARN ] GID 324931, Decrypt message from <146.190.161.228:51796> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.236332 [WARN ] GID 325918, Decrypt message from <18.246.46.106:54538> error: cannot decrypt message: no shared key yet
2023/03/26 15:31:13.236912 [WARN ] GID 325918, Decrypt message from <18.246.46.106:54538> error: cannot decrypt message: no shared key yet