EmonTx stopped being received by EmonPi, still indicates it's transmitting

EmonTx, located about 50 feet away, has been monitoring the pumps on my water system for two years. Recently it stopped being received by the EmonPi. Neither a reset nor a power cycle, after which the EmonTx indicates it is transmitting, corrects it. A reboot of the EmonPi was tried also and did not fix the problem. When the EmonTx is moved to within 6 feet of the EmonPi it works. There have been no new devices added here that operate on the 433 MHz frequency.

Hello @artic4ursa I assume the antennae are securely fitted? Might be worth checking the circuit boards around the radio modules for any signs of damage?