When logging onto a server it seems that the player data is missing. For each time I log in I end up at spawn with my inventory cleared.

Here is a bit from the server log:
[16:36:31] [Server thread/WARN]: Could not lookup user uuid for 99da556c-6d36-43e2-b0ff-f835737aafd2
com.mojang.authlib.yggdrasil.ProfileNotFoundException: Server did not find the requested profile
at com.mojang.authlib.yggdrasil.YggdrasilGameProfileRepository.findProfilesByNames(YggdrasilGameProfileRepository.java:90) [minecraft_server.14w10b.jar:?]
at pe.a(SourceFile:57) [minecraft_server.14w10b.jar:?]
at pe.a(SourceFile:353) [minecraft_server.14w10b.jar:?]
at my.aF(SourceFile:426) [minecraft_server.14w10b.jar:?]
at my.g(SourceFile:145) [minecraft_server.14w10b.jar:?]
at net.minecraft.server.MinecraftServer.run(SourceFile:367) [minecraft_server.14w10b.jar:?]
at mp.run(SourceFile:667) [minecraft_server.14w10b.jar:?]
[16:36:31] [Server thread/INFO]: Preparing level "Newlands"
[16:36:31] [Server thread/INFO]: Preparing start region for level 0
[16:36:32] [Server thread/INFO]: Preparing spawn area: 0%
[16:36:33] [Server thread/INFO]: Done (2.221s)! For help, type "help" or "?"
[16:36:52] User Authenticator #1/INFO: UUID of player Dadoo158 is 99da556c6d3643e2b0fff835737aafd2