Error in Calling APIs after changing WSO2 Admin Password

Question

I have an issue with WSO2 API Manager v2.6.

let me describe my situation, I have two WSO2 API Managers(v2.6) with the following structure:

• First APIM: two servers containing one server for APIM Service and another for MYSQL Database Server.(URL: External.api.com)
• Second APIM: five servers containing one server for MYSQL, one for Nginx(load balancing), and three servers for APIM Service. (I used the Windows DFS System for replication of this path <APIM_HOME>repository/deployment/server/synapse-configs/ between these three Service Servers.) (URL: Internal.api.com)

(I had many published APIs on both APIMs)

I changed the admin password of these APIMs using Internal.api.com/carbon and External.api.com/carbon.

after this action, I had some errors in Calling my APIs and users couldn't access their APIs; so I change the admin password back to the previous password.

the strange thing was, my errors got fixed in my external APIM(the one with two servers) but not in my internal APIM(the one with five servers)

We used a test access token with infinite (-1) expiration time on both APIMs, after changing the admin password back, the problem in External Apim got automatically fixed, but for the internal APIM, we created a new token and changed on apps configurations.

can you help me to find out, what could be the reason of this problem?

thank you.