what does 333 mean

Error: Message: unknown error: net::ERR_PROXY_CONNECTION_FAILED (Session info: chrome=135.0.7049.114) Stacktrace: #0 0x5644c4f8975a #1 0x5644c4a3c4b0 #2 0x5644c4a33593 #3 0x5644c4a23c69 #4 0x5644c4a2596d #5 0x5644c4a23ffe #6 0x5644c4a2399e #7 0x5644c4a2364f #8 0x5644c4a214cf #9 0x5644c4a21c8a #10 0x5644c4a3f949 #11 0x5644c4ada1f5 #12 0x5644c4ab3592 #13 0x5644c4ad95e0 #14 0x5644c4ab3363 #15 0x5644c4a7fd63 #16 0x5644c4a809c1 #17 0x5644c4f4ea6b #18 0x5644c4f52951 #19 0x5644c4f36b62 #20 0x5644c4f534c4 #21 0x5644c4f1b13f #22 0x5644c4f776f8 #23 0x5644c4f778d6 #24 0x5644c4f885a6 #25 0x7fc6fb937ac3