Server crashing when starting it

Here is the full server log: https://mclo.gs/0oAY54I

Quote from Robert9157

Line 14638, the server ran out of memory. Try reducing the number of mods used and/or use another solution to reduce memory usage during startup.

Thank you. I reduced the amount of mods and now it works but while playing just now my server crashed and I got this error. It may be a memory issue as well but I was wondering what caused it? It seems like something with blue skies. https://mclo.gs/gYMGGgw