RabbitMQ UI is not loading up after restore

[Tarun Sai Kumar]

Hi Everyone,

I have RabbitMQ v4.1.2 and Erlang 27.3.4.1 running on Windows 10/11 OS.

 
-> I have backup of the RabbitMQ using hop Client [Definitions] and restored the definitions using "rabbitmqctl import_definitions jsonfile" with the same json definition file.

I see there is error as below in the logs, RabbitMQ UI does not load completely.

-> Could someone please provide insights on what could possibly be the issue and how to resolve it while restoring? (Attached screenshot for UI error after restore)

Errors:

2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>   crasher:
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     initial call: cowboy_stream_h:request_process/3
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     pid: <0.40159.0>
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     registered_name: []
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     exception error: no function clause matching
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>                      rabbit_data_coercion:to_map(undefined) (rabbit_data_coercion.erl, line 64)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in function  rabbit_mgmt_wm_overview:to_json/2 (rabbit_mgmt_wm_overview.erl, line 50)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in call from cowboy_rest:call/3 (src/cowboy_rest.erl, line 1572)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in call from cowboy_rest:set_resp_body/2 (src/cowboy_rest.erl, line 1455)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in call from cowboy_rest:upgrade/4 (src/cowboy_rest.erl, line 281)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in call from cowboy_stream_h:execute/3 (src/cowboy_stream_h.erl, line 310)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>       in call from cowboy_stream_h:request_process/3 (src/cowboy_stream_h.erl, line 299)
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     ancestors: [<0.40152.0>,<0.649.0>,<0.647.0>,<0.646.0>,<0.644.0>,
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>                   rabbit_web_dispatch_sup,<0.599.0>]
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     message_queue_len: 0
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     messages: []
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     links: [<0.40152.0>]
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     dictionary: []
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     trap_exit: false
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     status: running
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     heap_size: 6772
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     stack_size: 29
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>     reductions: 3103
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0>   neighbours:
2025-09-08 14:33:27.467000+05:30 [error] <0.40159.0> 
2025-09-08 14:33:27.469000+05:30 [error] <0.40152.0> Ranch listener {acceptor,{127,0,0,1},15671}, connection process <0.40152.0>, stream 6 had its request process <0.40159.0> exit with reason {function_clause,[{rabbit_data_coercion,to_map,[undefined],[{file,"rabbit_data_coercion.erl"},{line,64}]},{rabbit_mgmt_wm_overview,to_json,2,[{file,"rabbit_mgmt_wm_overview.erl"},{line,50}]},{cowboy_rest,call,3,[{file,"src/cowboy_rest.erl"},{line,1572}]},{cowboy_rest,set_resp_body,2,[{file,"src/cowboy_rest.erl"},{line,1455}]},{cowboy_rest,upgrade,4,[{file,"src/cowboy_rest.erl"},{line,281}]},{cowboy_stream_h,execute,3,[{file,"src/cowboy_stream_h.erl"},{line,310}]},{cowboy_stream_h,request_process,3,[{file,"src/cowboy_stream_h.erl"},{line,299}]},{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,329}]}]}
2025-09-08 14:33:27.469000+05:30 [error] <0.40152.0>