Can I max both my employers 401k AND my SEP sole-proprietor plan? Do they have separate limits or a combined yearly limit? I work 50% for myself and 50% for employer.

I have imported my W-2 from my employer and maxed out my 401k contribution there. I also have a sole proprietorship with no employees (not an LLC). TT asked if I wanted to contribute to my SEP. I clicked "maximize my contribution" and it gave me a total. Does the IRS consider this as 2 different jobs with 2 different contribution totals or am I unable to contribute at all to my SEP given that I maxed out 401k employer plan. Thanks!