Feeling dumb at work

This is not a technical question. Please forgive me if I am posting it in the wrong sub. I dont find a better place to ask this.

I am feeling very dumb at work. I did clear my interview honestly. It's a routing and switching job.

I am new to the job after 2 years of break, and my troubleshooting skills are not good enough. I get mocked by my colleagues and one guy even told me that I am dumb. I am feeling low and frustrated. Should I continue in this job ? Should I find another job ? Am I in a toxic environment or this is expected ? It feels like I cannot ask help if I am stuck with something.

Any suggestions or help is appreciated.

Thanks.