Web Client stuck in initializing 5.5

hi guys

Web client gives a lot of headaches and I know I can reset it by stop and start service but this is too much....I've done that a lot already

today I found that after using my user-password to log in web client is stuck at initializing....

by the way I already  increased memory and CPU, right now vCenter has 4 vCPUs and 12 GB RAM

any idea what logs to check? to fix this issue?

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thanks a lot