I get an error when loading a report from Report Server Power BI the first time in the day-every day

The first time in the day (every days) I want to access to my dashboards in  Power BI Report Server Portal, but I'm geting this message, but after arround 5 minutes I can access to my Portal normally (without doing nothing). 

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Request IDa422c359-774b-42fc-8d99-c33e2ecec1aa

Status code500

Service version/powerbi/libs

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