Hello Anjum,
I wish to know which version of wazuh are you using,
there is a configuration in Wazuh app that let you increase the timeout of the request, you can find it in Wazuh / Settings / Configuration under de name Request timeout

please try increasing this value.
If this doesn't work, you can perform some curl to the Wazuh API from the Kibana server, in order to check if only the app is getting timeout or is an issue with the API in general?
you can do these request
1 - to get the API token
TOKEN= curl -u wazuh-wui:wazuh-wui -k -X GET "https://<your-api-ip>:55000/security/user/authenticate" - replace wazuh-wui with your custom user and pass if it's necessary
2 - get manager info or agent antes list
curl -k -X GET "https://<HOST_IP>:55000/manager/info" -H "Authorization: Bearer $TOKEN"
or
curl -k -X GET "https://<HOST_IP>:55000/agents" -H "Authorization: Bearer $TOKEN"
Here is more info about the Wazuh API request
Please, let us know if this was useful.
Regards.