I can't accept the quest from galmar if anybody knows what to do please help me

i filmed it so you can see what my problem is: youtube.com/watch?v=LJSn5YjKpN8

The only advise I know of that frequently works in situations such as these is to reload a previous save.
make sure its a save from before you entered the area he is in.

wait a little time and then ask him again

Civil War questline is one of the buggiest questlines ever. I have the same problem with Galmar.

Please do not post Spoilers in General.

People come to General to learn about the game without learning about what happens in the game. If they want to know about what happens, that is what the Cheats, Hints and Spoilers section is for.

Do not use or ask about quest details or location specific details related to quests/puzzles/NPCs in your posts in this section. General is for discussing gameplay and mechanics. General topics about the the game include but are not limited to: races, items and their use, magic, enchanting, skills, perks, character builds, Skyrim specific Lore, criticism, praise, funny random things that happen, places from an esthetic standpoint and and other general topics.

Use the Spoilers Section if you have to post quest details or other spoilers or a thread about the same. Location specific details are also spoilers, this includes unique item/NPC locations and puzzles. The Spoilers section is also for exploits with character builds.

I will move this now.