[Backport to 7.0.2]- Internal Server error is raised while performing backup on a index node using cbbackupmgr

./cbbackupmgr config -a /tmp/backups -r example --include-data ojnEcQ_e%h6PSTcISl_-5-219000.ewjmBK-5-220000.19t9piCEahGf8mn-5-220000

Output - 

Backup repository `example` created successfully in archive `/tmp/backups`

./cbbackupmgr backup -a /tmp/backups -r example --cluster couchbase://10.112.205.102 --username Administrator --password password

Output - 

Backing up to '2021-06-14T07_57_20.552447117-07_00'

Transferring GSI index definitions for bucket 'ojnEcQ_e%h6PSTcISl_-5-219000'                                                                                                                                                                      0 items / 0B

[=                                                                                                                                                                                                                                                     ] 0.68%

Error backing up cluster: internal server error executing 'GET' request to '/api/v1/bucket/ojnEcQ_e%25h6PSTcISl_-5-219000/backup': {"code":"error","error":"Fail to retrieve local metadata from url 10.112.205.101:9102.","result":{}}

| Transfer

| --------

| Status | Avg Transfer Rate | Started At                        | Finished At                     | Duration |

| Failed | 0B                | Mon, 14 Jun 2021 07:57:20 -0700/s | Mon, 14 Jun 2021 07:57:20 -0700 | 371ms    |