Our clients also suffer from this even all clients working in LAN with their server on premises.

I have told one of the customers to connect via wired connection and then the number of disconnections decreased, but the client is still complaining.
log:
2020-08-26 08:42:23 Database not in Live Mode
2020-08-26 08:42:36 Incoming Connection from: 192.168.1.251:61024
2020-08-26 08:42:38 AID Login Failed 192.168.1.251:61024: AID
2020-08-26 08:42:47 AID Login @192.168.1.251
2020-08-26 08:43:23 Database not in Live Mode
2020-08-26 08:44:21 IRENA/THREAD(16) Report Kainoraštis
2020-08-26 08:44:22 IRENA/THREAD(16) 1 running reports, duration for PriceRn was 0.33 seconds, of which 0.00 was used in 0 steps
2020-08-26 08:44:44 IRENA/THREAD(17) Report Kainoraštis
2020-08-26 08:44:44 IRENA/THREAD(17) 1 running reports, duration for PriceRn was 0.21 seconds, of which 0.00 was used in 0 steps
2020-08-26 08:47:11 AID Incoming Re-Connection from: 192.168.1.169:61111

2020-08-26 08:47:12 Incoming Connection from: 192.168.1.169:61111
2020-08-26 08:47:13 AID Login @192.168.1.169
2020-08-26 08:53:58 SYSTEM Logoff 192.168.1.169:61111: the client closed the connection (1)

The last line shows the client has been disconnected for no reason.
We have fixed Database not in Live Mode issue manually in the technics, but it did not help.