SIP/2.0 481 Subscription does not exist

[HailRase]

Hello, dear developers. I encountered a problem with accepting NOTIFY when sending REFER to a sip server (SIP/2.0 481 Subscription does not exist). Please note that the SIP-server works correctly and sends me NOTIFY, but the UserAgent sends 481 to the SIP-server. Here is the sip log:
FONT=BOLD - messages sent by the user agent

REFER sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp SIP/2.0
Route: sip:r_S@xxx.xxx.xxx.xxx:5063;transport=wss;lr
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;branch=z9hG4bK2872272
Max-Forwards: 69
To: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2941 REFER
Refer-To: sip:xxx@xxx.xxx.xxx.xxx
Referred-By: sip:xxx@xxx.xxx.xxx.xxx
Contact: sip:h5v7usb2@4grp8l43ks7b.invalid;transport=ws;ob
Allow: INVITE,ACK,CANCEL,BYE,UPDATE,MESSAGE,OPTIONS,REFER,INFO,NOTIFY
Supported: outbound
User-Agent: JsSIP 3.10.1
Content-Length: 0

SIP/2.0 100 Trying
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;rport=64054;received=xxx.xxx.xxx.xxx;branch=z9hG4bK2872272
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
To: sip:xxx@xxx.xxx.xxx.xxx
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2941 REFER
Max-Forwards: 70
Content-Length: 0

SIP/2.0 401 Unauthorized
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;rport=64054;received=xxx.xxx.xxx.xxx;branch=z9hG4bK2872272
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
To: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2941 REFER
Max-Forwards: 70
Content-Length: 0
Contact: sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp
Supported: path
Allow: REGISTER,INVITE,ACK,CANCEL,BYE,REFER,NOTIFY,OPTIONS,INFO,SUBSCRIBE,MESSAGE,UPDATE
Www-Authenticate: Digest realm="b2b_1102__xxx.xxx.xxx.xxx", nonce="7VwXpxMA2WqaRgbdc9VjPTlNEWJ", algorithm=MD5, qop="auth", opaque="1WVpoo"

REFER sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp SIP/2.0
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;branch=z9hG4bK1389077
Max-Forwards: 69
To: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2942 REFER
Route: sip:r_S@xxx.xxx.xxx.xxx:5063;transport=wss;lr
Authorization: Digest algorithm=MD5, username="xxx", realm="b2b_1102__xxx.xxx.xxx.xxx", nonce="7VwXpxMA2WqaRgbdc9VjPTlNEWJ", uri="sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp", response="b02fd28d311f792db56f859691e35032", opaque="1WVpoo", qop=auth, cnonce="j4ae8b1ld7hn", nc=00000001
Refer-To: sip:xxx@xxx.xxx.xxx.xxx
Referred-By: sip:xxx@xxx.xxx.xxx.xxx
Contact: sip:h5v7usb2@4grp8l43ks7b.invalid;transport=ws;ob
Allow: INVITE,ACK,CANCEL,BYE,UPDATE,MESSAGE,OPTIONS,REFER,INFO,NOTIFY
Supported: outbound
User-Agent: JsSIP 3.10.1
Content-Length: 0

SIP/2.0 100 Trying
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;rport=64054;received=xxx.xxx.xxx.xxx;branch=z9hG4bK1389077
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
To: sip:xxx@xxx.xxx.xxx.xxx
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2942 REFER
Max-Forwards: 70
Content-Length: 0

SIP/2.0 202 Accepted
Via: SIP/2.0/WSS 4grp8l43ks7b.invalid;rport=64054;received=xxx.xxx.xxx.xxx;branch=z9hG4bK1389077
From: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
To: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
Call-ID: lhr645njc76mr2d15ed1
CSeq: 2942 REFER
Max-Forwards: 70
Content-Length: 0
Contact: sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp
Expires: 60
User-Agent: R 0.5.0

NOTIFY sip:h5v7usb2@4grp8l43ks7b.invalid;transport=ws;ob SIP/2.0
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx:5063;rport;branch=z9hG4bK42Uil4-3j2Kk2
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx:5090;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK44yGw4-1ry2Rb
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338580 NOTIFY
Max-Forwards: 69
Content-Length: 20
Contact: sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp
Content-Type: message/sipfrag
Event: refer;id=2942
User-Agent: R 0.5.0
Subscription-State: active;expires=180
SIP/2.0 100 Trying

SIP/2.0 481 Subscription does not exist
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx:5063;rport;branch=z9hG4bK42Uil4-3j2Kk2
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx:5090;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK44yGw4-1ry2Rb
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338580 NOTIFY
Supported: outbound
Content-Length: 0

NOTIFY sip:h5v7usb2@4grp8l43ks7b.invalid;transport=ws;ob SIP/2.0
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx:5063;rport;branch=z9hG4bK2EIHUM-3kU2hL
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx:5090;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK4eyLpw-a2BKEi
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338581 NOTIFY
Max-Forwards: 69
Content-Length: 21
Contact: sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp
Content-Type: message/sipfrag
Event: refer;id=2942
User-Agent: R 0.5.0
Subscription-State: active;expires=180
X-R-Referring-Call-Id: rEB-0Hl-7zRAb6-01-Zlv6Jbt7fsJUvqmIj84WJ0gQER9
SIP/2.0 180 Ringing

SIP/2.0 481 Subscription does not exist
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx;rport;branch=z9hG4bK2EIHUM-3kU2hL
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK4eyLpw-a2BKEi
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338581 NOTIFY
Supported: outbound
Content-Length: 0

NOTIFY sip:h5v7usb2@4grp8l43ks7b.invalid;transport=ws;ob SIP/2.0
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx:5063;rport;branch=z9hG4bK18P536-1uEJXk
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx:5090;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK2pUexs-2nrpEz
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338582 NOTIFY
Max-Forwards: 69
Content-Length: 16
Contact: sip:xxx@xxx.xxx.xxx.xxx:5090;transport=tcp
Content-Type: message/sipfrag
Event: refer;id=2942
User-Agent: R 0.5.0
Subscription-State: terminated;reason=noresource
X-R-Referring-Call-Id: rEB-0Hl-7zRAb6-01-Zlv6Jbt7fsJUvqmIj84WJ0gQER9
SIP/2.0 200 OK

SIP/2.0 481 Subscription does not exist
Via: SIP/2.0/WSS xxx.xxx.xxx.xxx:5063;rport;branch=z9hG4bK18P536-1uEJXk
Via: SIP/2.0/TCP xxx.xxx.xxx.xxx:5090;rport=51182;received=xxx.xxx.xxx.xxx;branch=z9hG4bK2pUexs-2nrpEz
To: sip:xxx@xxx.xxx.xxx.xxx;tag=tmqffmckjv
From: sip:xxx@xxx.xxx.xxx.xxx;tag=rB2-0Hm-4AeG
Call-ID: lhr645njc76mr2d15ed1
CSeq: 367338582 NOTIFY
Supported: outbound
Content-Length: 0

And this is my refer handler. Only requestSucceeded and requestFailed are triggered:
const onReferHandler = () => {
if (holdedCall) {
const referOptions: ReferOptions = {
eventHandlers: {
accepted: () => console.log("refer accepted"),
failed: () => console.log("refer failed"),
trying: () => console.log("refer trying"),
progress: () => console.log("refer progress"),
requestSucceeded: () => console.log('refer request succeeded'),
requestFailed: () => console.log("refer request failed"),
},
}
if (activeCalls[holdedCall]) {
console.log(activeCalls[holdedCall])
activeCalls[holdedCall].refer('sip:xxx@xxx.xxx.xxx.xxx', referOptions)
}
}
}
Thanks for your help!!!