Recently, I’ve been experiencing frequent disconnects and problems reconnecting to relays at least on some of my devices. I’m wondering whether something is up in general or whether the issue is related to my network.
All connectiontivity-related settings are at default, the GUI reports Listeners at 3/3, Discovery at 4/5 (with IPv6 not working but this is normal).
Without enabling debug logs, I can only see these lines in the normal log file:
2024-04-10 15:29:33 Established secure connection to PRZMVUL at 10.220.0.55:61695-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6IFUB3GOL72DDLP9DIEC2
2024-04-10 15:29:33 Device PRZMVUL client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device1" at 10.220.0.55:61695-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6IFUB3GOL72DDLP9DIEC2
2024-04-10 15:29:33 Detected 0 NAT services
2024-04-10 15:29:34 Established secure connection to UDPWEVD at 10.220.0.55:61699-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6KR9SM2O1PSLCF4U9SS80
2024-04-10 15:29:34 Device UDPWEVD client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device2" at 10.220.0.55:61699-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6KR9SM2O1PSLCF4U9SS80
2024-04-10 15:29:34 Established secure connection to 3KHRD6O at 10.220.0.55:61698-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TP6KHSTIV02FCKKI99V7AR6
2024-04-10 15:29:34 Device 3KHRD6O client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device3" at 10.220.0.55:61698-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TP6KHSTIV02FCKKI99V7AR6
2024-04-10 15:30:10 Joined relay relay://88.212.32.226:22067
2024-04-10 15:34:04 Lost primary connection to PRZMVUL at 10.220.0.55:61695-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6IFUB3GOL72DDLP9DIEC2: reading length: read tcp 10.220.0.55:61695->129.13.64.139:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (0 remain)
2024-04-10 15:34:04 Connection to PRZMVUL at 10.220.0.55:61695-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6IFUB3GOL72DDLP9DIEC2 closed: reading length: read tcp 10.220.0.55:61695->129.13.64.139:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
2024-04-10 15:34:04 Lost primary connection to UDPWEVD at 10.220.0.55:61699-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6KR9SM2O1PSLCF4U9SS80: reading message: read tcp 10.220.0.55:61699->51.68.152.163:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (0 remain)
2024-04-10 15:34:04 Connection to UDPWEVD at 10.220.0.55:61699-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TP6KR9SM2O1PSLCF4U9SS80 closed: reading message: read tcp 10.220.0.55:61699->51.68.152.163:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
2024-04-10 15:34:04 Lost primary connection to 3KHRD6O at 10.220.0.55:61698-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TP6KHSTIV02FCKKI99V7AR6: reading message: read tcp 10.220.0.55:61698->188.186.12.179:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (0 remain)
2024-04-10 15:34:04 Connection to 3KHRD6O at 10.220.0.55:61698-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TP6KHSTIV02FCKKI99V7AR6 closed: reading message: read tcp 10.220.0.55:61698->188.186.12.179:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
2024-04-10 15:34:49 Established secure connection to UDPWEVD at 10.220.0.55:62634-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB16O2P0UB6SCJB2FR50G
2024-04-10 15:34:49 Device UDPWEVD client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device2" at 10.220.0.55:62634-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB16O2P0UB6SCJB2FR50G
2024-04-10 15:34:49 Established secure connection to PRZMVUL at 10.220.0.55:62635-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB1MSQN0NPGM9Q5QJHTGU
2024-04-10 15:34:49 Device PRZMVUL client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device1" at 10.220.0.55:62635-129.13.64.139:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB1MSQN0NPGM9Q5QJHTGU
2024-04-10 15:34:50 Established secure connection to 3KHRD6O at 10.220.0.55:62636-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TQBCOG8598VQPRHD636KKHA
2024-04-10 15:34:50 Device 3KHRD6O client is "syncthing v1.27.6-dev.15.g25cde60f.dirty-tomasz86-v1.27.5" named "device3" at 10.220.0.55:62636-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TQBCOG8598VQPRHD636KKHA
2024-04-10 15:35:48 Lost primary connection to UDPWEVD at 10.220.0.55:62634-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB16O2P0UB6SCJB2FR50G: handling index-update for zmokc-hnhyd: zmokc-hnhyd: folder is not running (0 remain)
2024-04-10 15:35:48 Connection to UDPWEVD at 10.220.0.55:62634-51.68.152.163:443/relay-client/TLS1.3-TLS_AES_128_GCM_SHA256/WAN-P50-5U4TQBB16O2P0UB6SCJB2FR50G closed: handling index-update for zmokc-hnhyd: zmokc-hnhyd: folder is not running
2024-04-10 15:36:12 Lost primary connection to 3KHRD6O at 10.220.0.55:62636-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TQBCOG8598VQPRHD636KKHA: reading message: read tcp 10.220.0.55:62636->188.186.12.179:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond. (0 remain)
2024-04-10 15:36:12 Connection to 3KHRD6O at 10.220.0.55:62636-188.186.12.179:443/relay-client/TLS1.3-TLS_CHACHA20_POLY1305_SHA256/WAN-P50-5U4TQBCOG8598VQPRHD636KKHA closed: reading message: read tcp 10.220.0.55:62636->188.186.12.179:443: wsarecv: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond.
In one word, the connections seem very unstable. Transfers often stall and are usually slower than they used to be.
Has anyone got any ideas? 
. For some time, I’ve been contemplating running my own relay at home, and then point all devices to use it first, however this seems quite problematic without a static IP.