In order to connect to Tor on my iPad, I use the Orbot app. However, recently the app started constantly failing to connect with the following error messages (the IP addresses of the Tor bridges are redacted):
Jun 16 14:44:07.000 [warn] {NET} Proxy Client: unable to connect OR connection (handshaking (proxy)) with [REDACTED IP ADDRESS] ID=bnv78wTYyTE9MO72tTPFiTEb695mXvL2qOlKn3d7bCo RSA_ID=FA6669A8B8F31CADA558EC10791EDFAAC300A640 ("general SOCKS server failure")
Jun 16 14:44:08.000 [notice] {CONFIG} Bridge 'Sr2Bridge647' has both an IPv4 and an IPv6 address. Will prefer using its IPv4 address ([REDACTED IP ADDRESS]) based on the configured Bridge address.
Jun 16 14:44:09.000 [notice] {CONFIG} Bridge 'Sr2Bridge647' has both an IPv4 and an IPv6 address. Will prefer using its IPv4 address ([REDACTED IP ADDRESS]) based on the configured Bridge address.
Jun 16 14:45:02.000 [notice] {GENERAL} Interrupt: exiting cleanly.
and
2023/06/16 11:44:02 [NOTICE]: obfs4proxy-0.0.14 - launched
2023/06/16 11:44:05 [ERROR]: obfs4([scrubbed]:63595) - outgoing connection failed: handshake: ntor AUTH mismatch: Derived: 83c130f58a5a79ecf0c8c11e3bbd5c51d4204b83501e3114641a83d8fb130a6e Received:fa9d4e8bca65ff0161b58d005e02b8d3a4f73080be3f1d9079f56a97bdb4f6da.
2023/06/16 11:44:06 [ERROR]: obfs4([scrubbed]:63595) - outgoing connection failed: handshake: ntor AUTH mismatch: Derived: 10313bdc680ea68a3d558d104e9550b31ea0731a48613fa67395468107d8f457 Received:92ce0ee40ad785a68b98adcf424271710fa3656bf2860b1aa384b48962a95b9f.
2023/06/16 11:44:07 [ERROR]: obfs4([scrubbed]:63595) - outgoing connection failed: handshake: ntor AUTH mismatch: Derived: b45373c01ba945ce3f4ae89c41de6edf6aee860cb83c58c7a111152740b98029 Received:17082eab39819e9a777885c98ff5467077131ae6e21c6ec2d2a51d7f3f65880b.
2023/06/16 11:45:02 [NOTICE]: obfs4 Stop: synthesizing SIGINT and SIGTERM
2023/06/16 11:45:02 [NOTICE]: obfs4 - terminated
Full screenshots of the Orbot logs are below:
In order to connect to Tor, I use custom bridges that I receive through Tor’s Telegram bot. I am currently in Russia where direct access to Tor is blocked, so connecting through bridges is my only option.
The bridges uploaded to Orbot are freshly received from Tor. The problem seems not to be in the bridges themselves, because when I configure a Tor bridge on a PC, the connection works fine. I started having this problem on iOS and iPadOS relatively recently.
What may be causing the connection through Orbot to fail?
